Remove Tandem.GroupTandem and previous state pattern #87

chrisklus · 2019-04-17T20:23:31Z

From https://github.com/phetsims/phet-io/issues/1443. Tandem.GroupTandem was also marked as deprecated upon the completion of https://github.com/phetsims/phet-io/issues/1442.

In order for phet-io metadata file validation to work (without our current workaround), we need the usages of GroupTandem to be replaced with GroupMemberTandem.

UPDATE by @samreid: Here is a list of sims using createGroupTandem which should be converted to use PhetioGroup

Balloons and Static Electricity Remove Tandem.GroupTandem and previous state pattern balloons-and-static-electricity#477
Build an Atom Remove Tandem.GroupTandem and previous state pattern build-an-atom#221
Circuit Construction Kit
Friction
Molarity
Ohm's Law
Shred
Energy Skate Park

The text was updated successfully, but these errors were encountered:

chrisklus · 2019-11-13T18:37:03Z

We added a TODO in molecules-and-light for converting to use PhetioGroup

pixelzoom · 2020-02-11T19:33:28Z

I see this TODO in Tandem:

    getTermRegex() {
      return /^[a-zA-Z0-9~]+$/; // TODO: eliminate ~ once GroupTandem has been deleted, see https://github.com/phetsims/tandem/issues/87
    }

... and GroupTandem no longer appears to exist. Can this TODO now be addressed?

pixelzoom · 2020-02-11T19:34:31Z

Ah, never mind. GroupTandem is still an inner class of Tandem.

zepumph · 2020-05-29T02:19:23Z

Once this is done, we can work on https://github.com/phetsims/phet-io/issues/1675

zepumph · 2020-05-29T21:59:02Z

Once this is complete, we can delete the addChildElementDeprecated method from PhetioStateEngine.js

…dem#87

samreid · 2021-01-20T20:42:23Z

@zepumph and I discussed that it may be appropriate to undeprecate GroupTandem for cases like phetsims/balloons-and-static-electricity@e0dbeaa, I'll consider this as I continue.

samreid · 2021-01-23T21:40:21Z

For Friction, @zepumph recommended uninstrumenting the Atoms. When we looked closer, we saw that the tandem passed to Atom wasn't actually used. So I uninstrumented them, but testing in the state wrapper noticed that sometimes things get out of sync:

But that is a pre-existing problem and seems most appropriate to address once we focus on Friction. I'll commit this change to get rid of using the deprecated pattern and useless instrumentation.

samreid · 2021-01-23T22:32:57Z

Since energy skate park has validation: false, it is actually safe to use GroupTandem to create the control points and tracks. I considered that we may wish to wait until we revisit the sim to change this pattern, but perhaps I'll have a try at PhetioGroup to see how it goes.

UPDATE: The reason I brought it up--if I turn on validation, there are other problems upstream from the problem at-hand, making it more difficult to develop and test. That's a good argument for waiting until we revisit the sim.

UPDATE: Likewise, the state wrapper is not even working with the deprecated pattern, even with validation disabled.

…s/tandem#87

samreid · 2021-01-23T23:46:04Z

I converted EnergySkatePark to use PhetioGroup for the ControlPoints, Tracks and TrackNodes. The sim is running in standalone mode, and Studio seems to be working OK. I considered creating a branch to get reviewed before merging to master, but it is working well enough that I think we should commit to master soon.

Here's a patch of my current progress (needs self-review and cleanup)

Index: js/common/model/PremadeTracks.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/model/PremadeTracks.js b/js/common/model/PremadeTracks.js
--- a/js/common/model/PremadeTracks.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/model/PremadeTracks.js	(date 1611443758656)
@@ -16,7 +16,6 @@
 import Enumeration from '../../../../phet-core/js/Enumeration.js';
 import merge from '../../../../phet-core/js/merge.js';
 import energySkatePark from '../../energySkatePark.js';
-import ControlPoint from './ControlPoint.js';
 import Track from './Track.js';
 
 // constants
@@ -74,11 +73,11 @@
 
   /**
    * Create a set of control points that create a parabola shaped track.
-   * @param {Tandem} groupTandem
+   * @param {EnergySkateParkModel} model
    * @param {Object} [options]
    * @returns {ControlPoint[]}
    */
-  createParabolaControlPoints: ( groupTandem, options ) => {
+  createParabolaControlPoints: ( model, options ) => {
     options = merge( {
       trackHeight: 6, // largest height for the parabola
       trackWidth: 8, // width from the left most control point to the right most control point
@@ -98,22 +97,19 @@
     const p3Bounds = createCenteredLimitBounds( p3, END_BOUNDS_WIDTH, END_BOUNDS_HEIGHT );
 
     return [
-      new ControlPoint( p1.x, p1.y, {
+      model.controlPointGroup.createNextElement( p1.x, p1.y, {
         visible: options.p1Visible,
         limitBounds: p1Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } ),
-      new ControlPoint( p2.x, p2.y, {
+      model.controlPointGroup.createNextElement( p2.x, p2.y, {
         visible: options.p2Visible,
         limitBounds: p2Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } ),
-      new ControlPoint( p3.x, p3.y, {
+      model.controlPointGroup.createNextElement( p3.x, p3.y, {
         visible: options.p3Visible,
         limitBounds: p3Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } )
     ];
@@ -122,10 +118,11 @@
   /**
    * Create a set of control points which create a slope shaped track, touching the ground on the right side.
    *
-   * @param {Tandem} groupTandem
+   * @param {EnergySkateParkModel} model
+   * @param {Object} [options]
    * @returns {ControlPoint[]}
    */
-  createSlopeControlPoints: ( groupTandem, options ) => {
+  createSlopeControlPoints: ( model,  options ) => {
 
     options = merge( {
       trackWidth: 6,
@@ -143,19 +140,16 @@
     const p3Bounds = createRelativeSpaceBounds( p3, 0.5, 2.5, 3, 0 );
 
     return [
-      new ControlPoint( p1.x, p1.y, {
+      model.controlPointGroup.createNextElement( p1.x, p1.y, {
         limitBounds: p1Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } ),
-      new ControlPoint( p2.x, p2.y, {
+      model.controlPointGroup.createNextElement( p2.x, p2.y, {
         limitBounds: p2Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } ),
-      new ControlPoint( p3.x, p3.y, {
+      model.controlPointGroup.createNextElement( p3.x, p3.y, {
         limitBounds: p3Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } )
     ];
@@ -166,11 +160,11 @@
    * a but since the interpolation moves it down by that much and we don't want the skater to go below ground
    * while on the track. Numbers determined by trial and error.
    *
-   * @param {Tandem} groupTandem
+   * @param {EnergySkateParkModel} model
    * @param {Object} [options]
    * @returns {ControlPoint[]}
    */
-  createDoubleWellControlPoints: ( groupTandem, options ) => {
+  createDoubleWellControlPoints: ( model, options ) => {
     options = merge( {
       trackHeight: 5, // largest height for the well
       trackWidth: 8, // width from the left most control point to the right most control point
@@ -210,35 +204,30 @@
     const p5Bounds = createRelativeSpaceBounds( p5, 1.5, 1.0, options.p5UpSpacing, options.p5DownSpacing );
 
     return [
-      new ControlPoint( p1.x, p1.y, {
+      model.controlPointGroup.createNextElement( p1.x, p1.y, {
         limitBounds: p1Bounds,
         visible: options.p1Visible,
-        phetioState: false,
-        tandem: groupTandem.createNextTandem()
+        phetioState: false
       } ),
-      new ControlPoint( p2.x, p2.y, {
+      model.controlPointGroup.createNextElement( p2.x, p2.y, {
         limitBounds: p2Bounds,
         visible: options.p2Visible,
-        phetioState: false,
-        tandem: groupTandem.createNextTandem()
+        phetioState: false
       } ),
-      new ControlPoint( p3.x, p3.y, {
+      model.controlPointGroup.createNextElement( p3.x, p3.y, {
         limitBounds: p3Bounds,
         visible: options.p3Visible,
-        phetioState: false,
-        tandem: groupTandem.createNextTandem()
+        phetioState: false
       } ),
-      new ControlPoint( p4.x, p4.y, {
+      model.controlPointGroup.createNextElement( p4.x, p4.y, {
         limitBounds: p4Bounds,
         visible: options.p4Visible,
-        phetioState: false,
-        tandem: groupTandem.createNextTandem()
+        phetioState: false
       } ),
-      new ControlPoint( p5.x, p5.y, {
+      model.controlPointGroup.createNextElement( p5.x, p5.y, {
         limitBounds: p5Bounds,
         visible: options.p5Visible,
-        phetioState: false,
-        tandem: groupTandem.createNextTandem()
+        phetioState: false
       } )
     ];
   },
@@ -246,10 +235,11 @@
   /**
    * Create a set of control points that will form a track that takes the shape of a loop.
    *
-   * @param  {Tandem} groupTandem
+   * @param {EnergySkateParkModel} model
+   * @param {Object} [options]
    * @returns {Array.<ControlPoint>}
    */
-  createLoopControlPoints: ( groupTandem, options ) => {
+  createLoopControlPoints: ( model,  options ) => {
     options = merge( {
       trackWidth: 9,
       trackHeight: 6,
@@ -284,39 +274,32 @@
     const p7Bounds = createRelativeSpaceBounds( p7, 1.5, 0.5, 2, 3 );
 
     return [
-      new ControlPoint( p1.x, p1.y, {
+      model.controlPointGroup.createNextElement( p1.x, p1.y, {
         limitBounds: p1Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } ),
-      new ControlPoint( p2.x, p2.y, {
+      model.controlPointGroup.createNextElement( p2.x, p2.y, {
         limitBounds: p2Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } ),
-      new ControlPoint( p3.x, p3.y, {
+      model.controlPointGroup.createNextElement( p3.x, p3.y, {
         limitBounds: p3Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } ),
-      new ControlPoint( p4.x, p4.y, {
+      model.controlPointGroup.createNextElement( p4.x, p4.y, {
         limitBounds: p4Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } ),
-      new ControlPoint( p5.x, p5.y, {
+      model.controlPointGroup.createNextElement( p5.x, p5.y, {
         limitBounds: p5Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } ),
-      new ControlPoint( p6.x, p6.y, {
+      model.controlPointGroup.createNextElement( p6.x, p6.y, {
         limitBounds: p6Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } ),
-      new ControlPoint( p7.x, p7.y, {
+      model.controlPointGroup.createNextElement( p7.x, p7.y, {
         limitBounds: p7Bounds,
-        tandem: groupTandem.createNextTandem(),
         phetioState: false
       } )
     ];
@@ -325,11 +308,9 @@
   /**
    * Create a track from the provided control points.
    *
-   * @param  {EnergySkateParkModel} model
-   * @param  {Array.<Track>} modelTracks
-   * @param  {Array.<ControlPoint>} controlPoints
-   * @param  {Property.<Bounds2>} availableBoundsProperty
-   * @param  {object} options
+   * @param {EnergySkateParkModel} model
+   * @param {Array.<ControlPoint>} controlPoints
+   * @param {Object} [options]
    * @returns {Track}
    */
   createTrack( model, controlPoints, options ) {
@@ -337,8 +318,7 @@
   }
 };
 
-// @public
-// @static
+// @public @static
 PremadeTracks.TrackType = TrackType;
 
 energySkatePark.register( 'PremadeTracks', PremadeTracks );
Index: js/common/model/ControlPoint.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/model/ControlPoint.js b/js/common/model/ControlPoint.js
--- a/js/common/model/ControlPoint.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/model/ControlPoint.js	(date 1611444490687)
@@ -18,7 +18,6 @@
 import Tandem from '../../../../tandem/js/Tandem.js';
 import IOType from '../../../../tandem/js/types/IOType.js';
 import NullableIO from '../../../../tandem/js/types/NullableIO.js';
-import ReferenceIO from '../../../../tandem/js/types/ReferenceIO.js';
 import energySkatePark from '../../energySkatePark.js';
 
 class ControlPoint extends PhetioObject {
@@ -117,22 +116,27 @@
 
   /**
    * Create a new control point, identical to this one.
+   * TODO: https://github.com/phetsims/tandem/issues/87 is this reversed?  Maybe call on the model
    * @public
    *
-   * @param {Tandem} tandem
+   * @param {EnergySkateParkModel} model
    * @returns {ControlPoint}
    */
-  copy( tandem ) {
-    return new ControlPoint( this.positionProperty.value.x, this.positionProperty.value.y, {
-      tandem: tandem
-    } );
+  copy( model ) {
+    return model.controlPointGroup.createNextElement( this.positionProperty.value.x, this.positionProperty.value.y );
   }
 }
 
 ControlPoint.ControlPointIO = new IOType( 'ControlPointIO', {
   valueType: ControlPoint,
   documentation: 'A control point that can manipulate the track.',
-  supertype: ReferenceIO( IOType.ObjectIO )
+  toStateObject: controlPoint => {
+    return { x: controlPoint.positionProperty.value.x, y: controlPoint.positionProperty.value.y };
+  },
+  stateToArgsForConstructor: stateObject => {
+    assert && assert( typeof stateObject.x === 'number' );
+    return [ stateObject.x, stateObject.y ];
+  }
 } );
 
 energySkatePark.register( 'ControlPoint', ControlPoint );
Index: js/common/model/Track.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/model/Track.js b/js/common/model/Track.js
--- a/js/common/model/Track.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/model/Track.js	(date 1611443365033)
@@ -77,11 +77,11 @@
     const tandem = options.tandem;
 
     // @private
-    this.model = model;
     this.parents = parents;
     this.trackTandem = tandem;
 
     // @public (read-only) - see options
+    this.model = model;
     this.draggable = options.draggable;
     this.configurable = options.configurable;
     this.splittable = options.splittable;
Index: js/common/model/DebugTracks.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/model/DebugTracks.js b/js/common/model/DebugTracks.js
--- a/js/common/model/DebugTracks.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/model/DebugTracks.js	(date 1611443745611)
@@ -10,7 +10,6 @@
 import Vector2 from '../../../../dot/js/Vector2.js';
 import energySkatePark from '../../energySkatePark.js';
 import EnergySkateParkQueryParameters from '../EnergySkateParkQueryParameters.js';
-import ControlPoint from './ControlPoint.js';
 import Track from './Track.js';
 
 class DebugTracks {
@@ -22,16 +21,10 @@
    * @public
    *
    * @param {EnergySkateParkModel} model
-   * @param {Tandem} controlPointGroupTandem
-   * @param {Tandem} trackGroupTandem
    */
-  static init( model, controlPointGroupTandem, trackGroupTandem ) {
+  static init( model) {
     // Tracks to help demonstrate issues
 
-    const createControlPoint = ( x, y ) => {
-      return new ControlPoint( x, y, { tandem: controlPointGroupTandem.createNextTandem() } );
-    };
-
     let controlPoints = null;
     let track = null;
     if ( EnergySkateParkQueryParameters.testTrackIndex === 1 ) {
@@ -41,8 +34,8 @@
       model.skater.positionProperty.set( new Vector2( -5, 8 ) );
       model.skater.released( null, 0 );
 
-      controlPoints = [ createControlPoint( 3.9238282647584946, 3.1917866726296955 ), createControlPoint( 2.043971377459748, 4.847851073345259 ), createControlPoint( -1.116994633273702, 3.686296958855098 ), createControlPoint( -3.5806797853309487, 1.8639512522361352 ), createControlPoint( -5.982719141323793, 6.235364490161 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 3.9238282647584946, 3.1917866726296955 ), model.controlPointGroup.createNextElement( 2.043971377459748, 4.847851073345259 ), model.controlPointGroup.createNextElement( -1.116994633273702, 3.686296958855098 ), model.controlPointGroup.createNextElement( -3.5806797853309487, 1.8639512522361352 ), model.controlPointGroup.createNextElement( -5.982719141323793, 6.235364490161 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -55,8 +48,8 @@
       model.skater.positionProperty.set( new Vector2( -5, 7.7 ) );
       model.skater.released( null, 0 );
 
-      controlPoints = [ createControlPoint( 3.9238282647584946, 3.1917866726296955 ), createControlPoint( 2.043971377459748, 4.847851073345259 ), createControlPoint( -1.116994633273702, 3.686296958855098 ), createControlPoint( -3.5806797853309487, 1.8639512522361352 ), createControlPoint( -5.982719141323793, 6.235364490161 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 3.9238282647584946, 3.1917866726296955 ), model.controlPointGroup.createNextElement( 2.043971377459748, 4.847851073345259 ), model.controlPointGroup.createNextElement( -1.116994633273702, 3.686296958855098 ), model.controlPointGroup.createNextElement( -3.5806797853309487, 1.8639512522361352 ), model.controlPointGroup.createNextElement( -5.982719141323793, 6.235364490161 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -69,8 +62,8 @@
       model.skater.positionProperty.set( new Vector2( -5, 7.7 ) );
       model.skater.released( null, 0 );
 
-      controlPoints = [ createControlPoint( -1.8031842576028616, 3.53633273703041 ), createControlPoint( 1.7306618962432907, 2.8187991949910547 ), createControlPoint( 1.9246153846153842, 4.3405881037567084 ), createControlPoint( 3.834311270125223, 4.907529069767442 ), createControlPoint( 3.491162790697672, 1.0732177996422188 ), createControlPoint( -2.760107334525939, 1.461124776386404 ), createControlPoint( -5.162146690518783, 5.832538014311269 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( -1.8031842576028616, 3.53633273703041 ), model.controlPointGroup.createNextElement( 1.7306618962432907, 2.8187991949910547 ), model.controlPointGroup.createNextElement( 1.9246153846153842, 4.3405881037567084 ), model.controlPointGroup.createNextElement( 3.834311270125223, 4.907529069767442 ), model.controlPointGroup.createNextElement( 3.491162790697672, 1.0732177996422188 ), model.controlPointGroup.createNextElement( -2.760107334525939, 1.461124776386404 ), model.controlPointGroup.createNextElement( -5.162146690518783, 5.832538014311269 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -83,8 +76,8 @@
       model.skater.positionProperty.set( new Vector2( -5, 7.7 ) );
       model.skater.released( null, 0 );
 
-      controlPoints = [ createControlPoint( 4.639964221824686, 6.68294946332737 ), createControlPoint( 1.4173524150268335, 0.938942307692308 ), createControlPoint( -3.207692307692308, 3.997439624329159 ), createControlPoint( 3.2524508050089445, 3.9079226296958858 ), createControlPoint( 3.491162790697672, 1.0732177996422188 ), createControlPoint( -2.760107334525939, 1.461124776386404 ), createControlPoint( -5.162146690518783, 5.832538014311269 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 4.639964221824686, 6.68294946332737 ), model.controlPointGroup.createNextElement( 1.4173524150268335, 0.938942307692308 ), model.controlPointGroup.createNextElement( -3.207692307692308, 3.997439624329159 ), model.controlPointGroup.createNextElement( 3.2524508050089445, 3.9079226296958858 ), model.controlPointGroup.createNextElement( 3.491162790697672, 1.0732177996422188 ), model.controlPointGroup.createNextElement( -2.760107334525939, 1.461124776386404 ), model.controlPointGroup.createNextElement( -5.162146690518783, 5.832538014311269 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -97,8 +90,8 @@
       model.skater.positionProperty.set( new Vector2( -5, 7.7 ) );
       model.skater.released( null, 0 );
 
-      controlPoints = [ createControlPoint( 4.431091234347049, 7.9252447313977665 ), createControlPoint( 2.4169588550983896, 7.975935759156005 ), createControlPoint( -1.9874106197862114, 4.75700797278857 ), createControlPoint( 0.13992761930286512, 6.207060140642635 ), createControlPoint( 1.447191413237924, 1.0090653610430707 ), createControlPoint( -1.7008228980322002, 1.0717102008522177 ), createControlPoint( -5.37101967799642, 7.0748332823816655 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 4.431091234347049, 7.9252447313977665 ), model.controlPointGroup.createNextElement( 2.4169588550983896, 7.975935759156005 ), model.controlPointGroup.createNextElement( -1.9874106197862114, 4.75700797278857 ), model.controlPointGroup.createNextElement( 0.13992761930286512, 6.207060140642635 ), model.controlPointGroup.createNextElement( 1.447191413237924, 1.0090653610430707 ), model.controlPointGroup.createNextElement( -1.7008228980322002, 1.0717102008522177 ), model.controlPointGroup.createNextElement( -5.37101967799642, 7.0748332823816655 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -111,8 +104,8 @@
       model.skater.positionProperty.set( new Vector2( 5, 7.9 ) );
       model.skater.released( null, 0 );
 
-      controlPoints = [ createControlPoint( 5.147227191413236, 6.57851296958855 ), createControlPoint( 0.05887058823529401, 1.0476264705882334 ), createControlPoint( -1.9427294117647067, 2.637132352941175 ), createControlPoint( -3.1201411764705886, 6.404849999999999 ), createControlPoint( 0.5690823529411766, 6.071249999999999 ), createControlPoint( -2.3940705882352944, 1.3419794117647044 ), createControlPoint( -5.474964705882353, 6.5029676470588225 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 5.147227191413236, 6.57851296958855 ), model.controlPointGroup.createNextElement( 0.05887058823529401, 1.0476264705882334 ), model.controlPointGroup.createNextElement( -1.9427294117647067, 2.637132352941175 ), model.controlPointGroup.createNextElement( -3.1201411764705886, 6.404849999999999 ), model.controlPointGroup.createNextElement( 0.5690823529411766, 6.071249999999999 ), model.controlPointGroup.createNextElement( -2.3940705882352944, 1.3419794117647044 ), model.controlPointGroup.createNextElement( -5.474964705882353, 6.5029676470588225 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -125,8 +118,8 @@
       model.skater.positionProperty.set( new Vector2( 5, 7.9 ) );
       model.skater.released( null, 0 );
 
-      controlPoints = [ createControlPoint( 5.147227191413236, 6.57851296958855 ), createControlPoint( -0.43896196231781204, 1.7569427657305372 ), createControlPoint( -1.1787355229664587, 2.807585005572261 ), createControlPoint( -3.1201411764705886, 6.404849999999999 ), createControlPoint( 0.5690823529411766, 6.071249999999999 ), createControlPoint( -2.3940705882352944, 1.3419794117647044 ), createControlPoint( -5.474964705882353, 6.5029676470588225 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 5.147227191413236, 6.57851296958855 ), model.controlPointGroup.createNextElement( -0.43896196231781204, 1.7569427657305372 ), model.controlPointGroup.createNextElement( -1.1787355229664587, 2.807585005572261 ), model.controlPointGroup.createNextElement( -3.1201411764705886, 6.404849999999999 ), model.controlPointGroup.createNextElement( 0.5690823529411766, 6.071249999999999 ), model.controlPointGroup.createNextElement( -2.3940705882352944, 1.3419794117647044 ), model.controlPointGroup.createNextElement( -5.474964705882353, 6.5029676470588225 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -139,8 +132,8 @@
       model.skater.positionProperty.set( new Vector2( 5, 7.9 ) );
       model.skater.released( null, 0 );
 
-      controlPoints = [ createControlPoint( 5.07086859688196, 6.925682071269487 ), createControlPoint( 2.061781737193762, 0.7625271732714408 ), createControlPoint( 0.09287305122494338, 0.7625271732714408 ), createControlPoint( -3.287706013363029, 3.0472042334050697 ), createControlPoint( -2.2289532293986642, 4.399535077951003 ), createControlPoint( -0.6129621380846331, 4.306662026726059 ), createControlPoint( 0.7429844097995542, 3.3629726075698803 ), createControlPoint( 0.14859688195991083, 2.3227944338505053 ), createControlPoint( -1.4302449888641426, 1.4159674088426304 ), createControlPoint( -4.532204899777283, 0.580109947818132 ), createControlPoint( -6.1185746102449885, 7.75698912376468 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 5.07086859688196, 6.925682071269487 ), model.controlPointGroup.createNextElement( 2.061781737193762, 0.7625271732714408 ), model.controlPointGroup.createNextElement( 0.09287305122494338, 0.7625271732714408 ), model.controlPointGroup.createNextElement( -3.287706013363029, 3.0472042334050697 ), model.controlPointGroup.createNextElement( -2.2289532293986642, 4.399535077951003 ), model.controlPointGroup.createNextElement( -0.6129621380846331, 4.306662026726059 ), model.controlPointGroup.createNextElement( 0.7429844097995542, 3.3629726075698803 ), model.controlPointGroup.createNextElement( 0.14859688195991083, 2.3227944338505053 ), model.controlPointGroup.createNextElement( -1.4302449888641426, 1.4159674088426304 ), model.controlPointGroup.createNextElement( -4.532204899777283, 0.580109947818132 ), model.controlPointGroup.createNextElement( -6.1185746102449885, 7.75698912376468 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -154,8 +147,8 @@
       model.skater.released( null, 0 );
       model.frictionProperty.value = 0;
 
-      controlPoints = [ createControlPoint( 5.516659242761692, 5.458287861915368 ), createControlPoint( 2.061781737193762, 0.7625271732714408 ), createControlPoint( 0.09287305122494338, 0.7625271732714408 ), createControlPoint( -3.287706013363029, 3.0472042334050697 ), createControlPoint( -2.2289532293986642, 4.399535077951003 ), createControlPoint( -0.6129621380846331, 4.306662026726059 ), createControlPoint( 0.7429844097995542, 3.3629726075698803 ), createControlPoint( 0.14859688195991083, 2.3227944338505053 ), createControlPoint( -1.4302449888641426, 1.4159674088426304 ), createControlPoint( -4.532204899777283, 0.580109947818132 ), createControlPoint( -6.1185746102449885, 7.75698912376468 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 5.516659242761692, 5.458287861915368 ), model.controlPointGroup.createNextElement( 2.061781737193762, 0.7625271732714408 ), model.controlPointGroup.createNextElement( 0.09287305122494338, 0.7625271732714408 ), model.controlPointGroup.createNextElement( -3.287706013363029, 3.0472042334050697 ), model.controlPointGroup.createNextElement( -2.2289532293986642, 4.399535077951003 ), model.controlPointGroup.createNextElement( -0.6129621380846331, 4.306662026726059 ), model.controlPointGroup.createNextElement( 0.7429844097995542, 3.3629726075698803 ), model.controlPointGroup.createNextElement( 0.14859688195991083, 2.3227944338505053 ), model.controlPointGroup.createNextElement( -1.4302449888641426, 1.4159674088426304 ), model.controlPointGroup.createNextElement( -4.532204899777283, 0.580109947818132 ), model.controlPointGroup.createNextElement( -6.1185746102449885, 7.75698912376468 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -168,8 +161,8 @@
       model.skater.released( null, 0 );
       model.frictionProperty.value = 0.0363651226158039;
 
-      controlPoints = [ createControlPoint( 5.07086859688196, 6.925682071269487 ), createControlPoint( 2.061781737193762, 0.7625271732714408 ), createControlPoint( 0.09287305122494338, 0.7625271732714408 ), createControlPoint( -3.287706013363029, 3.0472042334050697 ), createControlPoint( -2.2289532293986642, 4.399535077951003 ), createControlPoint( -0.6129621380846331, 4.306662026726059 ), createControlPoint( 0.7429844097995542, 3.3629726075698803 ), createControlPoint( 0.14859688195991083, 2.3227944338505053 ), createControlPoint( -1.4302449888641426, 1.4159674088426304 ), createControlPoint( -4.532204899777283, 0.580109947818132 ), createControlPoint( -6.1185746102449885, 7.75698912376468 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 5.07086859688196, 6.925682071269487 ), model.controlPointGroup.createNextElement( 2.061781737193762, 0.7625271732714408 ), model.controlPointGroup.createNextElement( 0.09287305122494338, 0.7625271732714408 ), model.controlPointGroup.createNextElement( -3.287706013363029, 3.0472042334050697 ), model.controlPointGroup.createNextElement( -2.2289532293986642, 4.399535077951003 ), model.controlPointGroup.createNextElement( -0.6129621380846331, 4.306662026726059 ), model.controlPointGroup.createNextElement( 0.7429844097995542, 3.3629726075698803 ), model.controlPointGroup.createNextElement( 0.14859688195991083, 2.3227944338505053 ), model.controlPointGroup.createNextElement( -1.4302449888641426, 1.4159674088426304 ), model.controlPointGroup.createNextElement( -4.532204899777283, 0.580109947818132 ), model.controlPointGroup.createNextElement( -6.1185746102449885, 7.75698912376468 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -182,8 +175,8 @@
       model.skater.released( null, 0 );
       model.frictionProperty.value = 0.0363651226158039;
 
-      controlPoints = [ createControlPoint( 7.049477756286265, 5.232410541586074 ), createControlPoint( 1.8198088164974369, 1.7349575399795614 ), createControlPoint( -0.14909986947138165, 1.7349575399795614 ), createControlPoint( 0.5162088974854928, 1.8286581237911035 ), createControlPoint( -0.4516827852998073, 11.657297387984716 ), createControlPoint( 2.0970986460348158, 5.6886320108087025 ), createControlPoint( -1.8000003436635232, 4.708138438138744 ), createControlPoint( -0.43555125725338684, 5.914473403458605 ), createControlPoint( -2.500386847195358, 4.849792552394775 ), createControlPoint( -4.774177820473608, 1.5525403145262526 ), createControlPoint( -6.339690522243714, 8.797478239845262 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 7.049477756286265, 5.232410541586074 ), model.controlPointGroup.createNextElement( 1.8198088164974369, 1.7349575399795614 ), model.controlPointGroup.createNextElement( -0.14909986947138165, 1.7349575399795614 ), model.controlPointGroup.createNextElement( 0.5162088974854928, 1.8286581237911035 ), model.controlPointGroup.createNextElement( -0.4516827852998073, 11.657297387984716 ), model.controlPointGroup.createNextElement( 2.0970986460348158, 5.6886320108087025 ), model.controlPointGroup.createNextElement( -1.8000003436635232, 4.708138438138744 ), model.controlPointGroup.createNextElement( -0.43555125725338684, 5.914473403458605 ), model.controlPointGroup.createNextElement( -2.500386847195358, 4.849792552394775 ), model.controlPointGroup.createNextElement( -4.774177820473608, 1.5525403145262526 ), model.controlPointGroup.createNextElement( -6.339690522243714, 8.797478239845262 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -196,8 +189,8 @@
       model.skater.released( null, 0 );
       model.frictionProperty.value = 0.0363651226158039;
 
-      controlPoints = [ createControlPoint( 0.8301088646967347, 3.5809234059097967 ), createControlPoint( 3.411228615863142, 2.4784350699844477 ), createControlPoint( 5.29194401244168, 5.928575038880248 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 0.8301088646967347, 3.5809234059097967 ), model.controlPointGroup.createNextElement( 3.411228615863142, 2.4784350699844477 ), model.controlPointGroup.createNextElement( 5.29194401244168, 5.928575038880248 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -210,8 +203,8 @@
       model.skater.released( null, 0 );
       model.frictionProperty.value = 0.0363651226158039;
 
-      controlPoints = [ createControlPoint( 0.8301088646967347, 3.5809234059097967 ), createControlPoint( 3.411228615863142, 2.4784350699844477 ), createControlPoint( 5.29194401244168, 5.928575038880248 ) ];
-      track = new Track( model, controlPoints, null, { tandem: trackGroupTandem.createNextTandem() } );
+      controlPoints = [ model.controlPointGroup.createNextElement( 0.8301088646967347, 3.5809234059097967 ), model.controlPointGroup.createNextElement( 3.411228615863142, 2.4784350699844477 ), model.controlPointGroup.createNextElement( 5.29194401244168, 5.928575038880248 ) ];
+      track = model.trackGroup.createNextElement( controlPoints, null );
       track.physicalProperty.value = true;
       model.tracks.add( track );
     }
@@ -223,31 +216,31 @@
       model.frictionProperty.value = 0.05;
 
       const controlPoints1 = [
-        createControlPoint( -6.23, -0.85 ),
-        createControlPoint( -5.23, -0.85 ),
-        createControlPoint( -4.23, -0.85 )
+        model.controlPointGroup.createNextElement( -6.23, -0.85 ),
+        model.controlPointGroup.createNextElement( -5.23, -0.85 ),
+        model.controlPointGroup.createNextElement( -4.23, -0.85 )
       ];
-      const track1 = new Track( model, controlPoints1, null, { tandem: trackGroupTandem.createNextTandem() } );
+      const track1 = model.trackGroup.createNextElement( controlPoints1, null );
       track1.physicalProperty.value = false;
       model.tracks.add( track1 );
 
       const controlPoints2 = [
-        createControlPoint( -6.23, -0.85 ),
-        createControlPoint( -5.23, -0.85 ),
-        createControlPoint( -4.23, -0.85 )
+        model.controlPointGroup.createNextElement( -6.23, -0.85 ),
+        model.controlPointGroup.createNextElement( -5.23, -0.85 ),
+        model.controlPointGroup.createNextElement( -4.23, -0.85 )
       ];
-      const track2 = new Track( model, controlPoints2, null, { tandem: trackGroupTandem.createNextTandem() } );
+      const track2 = model.trackGroup.createNextElement( controlPoints2, null );
       track2.physicalProperty.value = false;
       model.tracks.add( track2 );
 
       const controlPoints3 = [
-        createControlPoint( -0.720977917981072, 1.6368312846731214 ),
-        createControlPoint( 0.279022082018928, 1.6368312846731214 ),
-        createControlPoint( 3.8511345589035137, 7.315696725769607 ),
-        createControlPoint( -1.1916066572392037, 2.911932992494288 ),
-        createControlPoint( -9.170190362232134, 6.469483302512781 )
+        model.controlPointGroup.createNextElement( -0.720977917981072, 1.6368312846731214 ),
+        model.controlPointGroup.createNextElement( 0.279022082018928, 1.6368312846731214 ),
+        model.controlPointGroup.createNextElement( 3.8511345589035137, 7.315696725769607 ),
+        model.controlPointGroup.createNextElement( -1.1916066572392037, 2.911932992494288 ),
+        model.controlPointGroup.createNextElement( -9.170190362232134, 6.469483302512781 )
       ];
-      const track3 = new Track( model, controlPoints3, null, { tandem: trackGroupTandem.createNextTandem() } );
+      const track3 = model.trackGroup.createNextElement( controlPoints3, null );
       track3.physicalProperty.value = true;
       model.tracks.add( track3 );
     }
@@ -258,13 +251,13 @@
       model.skater.positionProperty.set( new Vector2( -6.698445595854922, 6.5278756476683935 ) );
       model.skater.released( null, 0 );
       model.frictionProperty.value = 0;
-      const track15 = new Track( model, [
-        createControlPoint( 0.9873551637279601, 7.856892317380353 ),
-        createControlPoint( -0.4621662468513845, 5.9031895465994975 ),
-        createControlPoint( -3.0250881612090676, 5.735129093198994 ),
-        createControlPoint( -4.705692695214106, 0.9454061712846356 ),
-        createControlPoint( -7.310629722921914, 7.457748740554157 )
-      ], null, { tandem: trackGroupTandem.createNextTandem() } );
+      const track15 = model.trackGroup.createNextElement( [
+        model.controlPointGroup.createNextElement( 0.9873551637279601, 7.856892317380353 ),
+        model.controlPointGroup.createNextElement( -0.4621662468513845, 5.9031895465994975 ),
+        model.controlPointGroup.createNextElement( -3.0250881612090676, 5.735129093198994 ),
+        model.controlPointGroup.createNextElement( -4.705692695214106, 0.9454061712846356 ),
+        model.controlPointGroup.createNextElement( -7.310629722921914, 7.457748740554157 )
+      ], null );
       track15.physicalProperty.value = true;
       model.tracks.add( track15 );
     }
@@ -273,20 +266,19 @@
       model.frictionProperty.value = 0;
 
       const controlPoints = [
-        createControlPoint( -0.29564715581203593, 5.349320898598515 ),
-        createControlPoint( 0.5844187963726313, 5.266814715581202 ),
-        createControlPoint( 1.5469909315746087, 4.771777617477328 ),
-        createControlPoint( 2.0145259686727126, 3.1629070486397355 ),
-        createControlPoint( 1.2307172300082456, 1.7878039983511949 ),
-        createControlPoint( -1.2994723825226702, 1.7740529678483092 ),
-        createControlPoint( -2.1382852431986805, 3.575437963726298 ),
-        createControlPoint( -1.0382028029678487, 5.280565746084088 ),
-        createControlPoint( 0.6944270403957145, 6.806930131904369 ),
-        createControlPoint( -0.9831986809563062, 7.962016694146743 )
+        model.controlPointGroup.createNextElement( -0.29564715581203593, 5.349320898598515 ),
+        model.controlPointGroup.createNextElement( 0.5844187963726313, 5.266814715581202 ),
+        model.controlPointGroup.createNextElement( 1.5469909315746087, 4.771777617477328 ),
+        model.controlPointGroup.createNextElement( 2.0145259686727126, 3.1629070486397355 ),
+        model.controlPointGroup.createNextElement( 1.2307172300082456, 1.7878039983511949 ),
+        model.controlPointGroup.createNextElement( -1.2994723825226702, 1.7740529678483092 ),
+        model.controlPointGroup.createNextElement( -2.1382852431986805, 3.575437963726298 ),
+        model.controlPointGroup.createNextElement( -1.0382028029678487, 5.280565746084088 ),
+        model.controlPointGroup.createNextElement( 0.6944270403957145, 6.806930131904369 ),
+        model.controlPointGroup.createNextElement( -0.9831986809563062, 7.962016694146743 )
       ];
 
-      const track16 = new Track( model, controlPoints, null, {
-        tandem: trackGroupTandem.createNextTandem(),
+      const track16 = model.trackGroup.createNextElement( controlPoints, null, {
         configurable: true
       } );
       track16.physicalProperty.value = true;
Index: js/graphs/model/GraphsModel.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/graphs/model/GraphsModel.js b/js/graphs/model/GraphsModel.js
--- a/js/graphs/model/GraphsModel.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/graphs/model/GraphsModel.js	(date 1611443745590)
@@ -308,13 +308,12 @@
    * @returns {Track[]}
    */
   createGraphsTrackSet( tandem ) {
-    const groupTandem = this.controlPointGroupTandem;
 
     // all tracks in graphs screen are bound by these dimensions (in meters)
     const trackHeight = GraphsConstants.TRACK_HEIGHT;
     const trackWidth = GraphsConstants.TRACK_WIDTH;
 
-    const parabolaControlPoints = PremadeTracks.createParabolaControlPoints( groupTandem, {
+    const parabolaControlPoints = PremadeTracks.createParabolaControlPoints( this, {
       trackHeight: trackHeight,
       trackWidth: trackWidth,
       p1Visible: false,
@@ -327,7 +326,7 @@
       phetioState: false
     } );
 
-    const doubleWellControlPoints = PremadeTracks.createDoubleWellControlPoints( groupTandem, {
+    const doubleWellControlPoints = PremadeTracks.createDoubleWellControlPoints( this, {
       trackHeight: 4,
       trackWidth: 10,
       trackMidHeight: 1.5,
Index: js/common/view/TrackNode.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/view/TrackNode.js b/js/common/view/TrackNode.js
--- a/js/common/view/TrackNode.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/view/TrackNode.js	(date 1611443421787)
@@ -26,14 +26,14 @@
 class TrackNode extends Node {
 
   /**
-   * @param {EnergySkateParkModel} model the entire model.
    * @param {Track} track the track for this track node
    * @param {ModelViewTransform2} modelViewTransform the model view transform for the view
    * @param {Property.<Bounds2>} availableBoundsProperty
    * @param {Tandem} tandem
    * @param {Object} [options]
    */
-  constructor( model, track, modelViewTransform, availableBoundsProperty, tandem, options ) {
+  constructor( track, modelViewTransform, availableBoundsProperty, tandem, options ) {
+    const model = track.model;
 
     options = merge( {
 
Index: js/common/view/EnergySkateParkTrackSetScreenView.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/view/EnergySkateParkTrackSetScreenView.js b/js/common/view/EnergySkateParkTrackSetScreenView.js
--- a/js/common/view/EnergySkateParkTrackSetScreenView.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/view/EnergySkateParkTrackSetScreenView.js	(date 1611443745615)
@@ -23,7 +23,7 @@
     super( model, tandem, options );
 
     const trackNodes = model.tracks.map( track => {
-      return new TrackNode( model, track, this.modelViewTransform, this.availableModelBoundsProperty, this.trackNodeGroupTandem.createNextTandem() );
+      return this.trackNodeGroup.createNextElement( track, this.modelViewTransform, this.availableModelBoundsProperty);
     } );
 
     trackNodes.forEach( trackNode => {
Index: js/common/view/TrackToolboxPanel.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/view/TrackToolboxPanel.js b/js/common/view/TrackToolboxPanel.js
--- a/js/common/view/TrackToolboxPanel.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/view/TrackToolboxPanel.js	(date 1611443953966)
@@ -35,7 +35,7 @@
         interactive: false
       }
     } );
-    const iconNode = new TrackNode( model, iconTrack, view.modelViewTransform, model.availableModelBoundsProperty, tandem.createTandem( 'iconNode' ), {
+    const iconNode = new TrackNode( iconTrack, view.modelViewTransform, model.availableModelBoundsProperty, tandem.createTandem( 'iconNode' ), {
 
       // want the icon to look pickable, even though it isn't really draggable (forwarding listener makes the new
       // TrackNode draggable)
Index: js/common/view/SceneSelectionRadioButtonGroup.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/view/SceneSelectionRadioButtonGroup.js b/js/common/view/SceneSelectionRadioButtonGroup.js
--- a/js/common/view/SceneSelectionRadioButtonGroup.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/view/SceneSelectionRadioButtonGroup.js	(date 1611443919879)
@@ -69,7 +69,7 @@
 
       let track = null;
       if ( trackType === PremadeTracks.TrackType.PARABOLA ) {
-        const parabolaControlPoints = PremadeTracks.createParabolaControlPoints( model.controlPointGroupTandem, merge( {
+        const parabolaControlPoints = PremadeTracks.createParabolaControlPoints( model, merge( {
           trackMidHeight: 1
         }, controlPointOptions ) );
         track = EnergySkateParkTrackSetModel.createPremadeTrack( model, parabolaControlPoints, {
@@ -77,19 +77,19 @@
         } );
       }
       else if ( trackType === PremadeTracks.TrackType.SLOPE ) {
-        const slopeControlPoints = PremadeTracks.createSlopeControlPoints( model.controlPointGroupTandem, controlPointOptions );
+        const slopeControlPoints = PremadeTracks.createSlopeControlPoints( model, controlPointOptions );
         track = EnergySkateParkTrackSetModel.createPremadeTrack( model, slopeControlPoints, {
           tandem: tandem.createTandem( 'slopeTrackIcon' )
         } );
       }
       else if ( trackType === PremadeTracks.TrackType.DOUBLE_WELL ) {
-        const doubleWellControlPoints = PremadeTracks.createDoubleWellControlPoints( model.controlPointGroupTandem, controlPointOptions);
+        const doubleWellControlPoints = PremadeTracks.createDoubleWellControlPoints( model, controlPointOptions);
         track = EnergySkateParkTrackSetModel.createPremadeTrack( model, doubleWellControlPoints, {
           tandem: tandem.createTandem( 'doubleWellTrackIcon' )
         } );
       }
       else if ( trackType === PremadeTracks.TrackType.LOOP ) {
-        const loopControlPoints = PremadeTracks.createLoopControlPoints( model.controlPointGroupTandem, merge( {
+        const loopControlPoints = PremadeTracks.createLoopControlPoints( model, merge( {
           innerLoopWidth: 2.5,
           innerLoopTop: 3.5
         }, controlPointOptions ) );
@@ -114,9 +114,8 @@
         children.push( background );
       }
 
-      // const track = model.tracks.get( index );
       const track = createIconTrack( model.trackTypes[ index ] );
-      const trackNode = new TrackNode( model, track, view.modelViewTransform, new Property(), tandem.createTandem( 'trackNode' + index ), {
+      const trackNode = new TrackNode( track, view.modelViewTransform, new Property(), tandem.createTandem( 'trackNode' + index ), {
         isIcon: true
       } );
 
Index: js/common/view/EnergySkateParkScreenView.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/view/EnergySkateParkScreenView.js b/js/common/view/EnergySkateParkScreenView.js
--- a/js/common/view/EnergySkateParkScreenView.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/view/EnergySkateParkScreenView.js	(date 1611444753146)
@@ -29,10 +29,12 @@
 import Path from '../../../../scenery/js/nodes/Path.js';
 import Text from '../../../../scenery/js/nodes/Text.js';
 import RectangularPushButton from '../../../../sun/js/buttons/RectangularPushButton.js';
+import PhetioGroup from '../../../../tandem/js/PhetioGroup.js';
 import skaterIconImage from '../../../images/skater1_left_png.js';
 import energySkatePark from '../../energySkatePark.js';
 import energySkateParkStrings from '../../energySkateParkStrings.js';
 import EnergySkateParkConstants from '../EnergySkateParkConstants.js';
+import Track from '../model/Track.js';
 import AttachDetachToggleButtons from './AttachDetachToggleButtons.js';
 import BackgroundNode from './BackgroundNode.js';
 import EnergyBarGraphAccordionBox from './EnergyBarGraphAccordionBox.js';
@@ -44,6 +46,7 @@
 import ReferenceHeightLine from './ReferenceHeightLine.js';
 import SkaterNode from './SkaterNode.js';
 import ToolboxPanel from './ToolboxPanel.js';
+import TrackNode from './TrackNode.js';
 import VisibilityControlsPanel from './VisibilityControlsPanel.js';
 
 const controlsRestartSkaterString = energySkateParkStrings.skaterControls.restartSkater;
@@ -109,8 +112,37 @@
       tandem: tandem
     } );
 
-    // @protected
-    this.trackNodeGroupTandem = tandem.createGroupTandem( 'trackNode' );
+    const modelPoint = new Vector2( 0, 0 );
+
+    // earth is 86px high in stage coordinates
+    const viewPoint = new Vector2( this.layoutBounds.width / 2, this.layoutBounds.height - BackgroundNode.earthHeight );
+
+    // scale chosen so that displayed model is the same as it was for energy-skate-park-basics when that sim
+    // used non-default layout bounds
+    const scale = 61.40;
+    const modelViewTransform = ModelViewTransform2.createSinglePointScaleInvertedYMapping( modelPoint, viewPoint, scale );
+    this.modelViewTransform = modelViewTransform;
+
+    this.availableModelBoundsProperty = new Property( new Bounds2( 0, 0, 0, 0 ), {
+      valueType: [ Bounds2 ]
+    } );
+    this.availableModelBoundsProperty.link( bounds => {
+      model.availableModelBoundsProperty.set( bounds );
+    } );
+
+    // @public {PhetioGroup.<Track>} group of TrackNodes
+    this.trackNodeGroup = new PhetioGroup( ( tandem, track, modelViewTransform, availableBoundsProperty, options ) => {
+      assert && options && assert( !options.hasOwnProperty( 'tandem' ), 'tandem is managed by the PhetioGroup' );
+      return new TrackNode( track, modelViewTransform, availableBoundsProperty, tandem, options );
+    }, [ model.trackGroup.archetype, modelViewTransform, this.availableModelBoundsProperty, {} ], {
+      tandem: tandem.createTandem( 'trackNodes' ),
+      phetioType: PhetioGroup.PhetioGroupIO( Node.NodeIO ),
+      phetioDynamicElementName: 'trackNode',
+
+      // These elements are not created by the PhET-IO state engine, they can just listen to the model for supporting
+      // state in the same way they do for sim logic.
+      supportsDynamicState: false
+    } );
 
     // @protected
     this.model = model;
@@ -136,24 +168,6 @@
     this.topLayer = new Node();
     this.children = [ this.bottomLayer, this.topLayer ];
 
-    const modelPoint = new Vector2( 0, 0 );
-
-    // earth is 86px high in stage coordinates
-    const viewPoint = new Vector2( this.layoutBounds.width / 2, this.layoutBounds.height - BackgroundNode.earthHeight );
-
-    // scale chosen so that displayed model is the same as it was for energy-skate-park-basics when that sim
-    // used non-default layout bounds
-    const scale = 61.40;
-    const modelViewTransform = ModelViewTransform2.createSinglePointScaleInvertedYMapping( modelPoint, viewPoint, scale );
-    this.modelViewTransform = modelViewTransform;
-
-    this.availableModelBoundsProperty = new Property( new Bounds2( 0, 0, 0, 0 ), {
-      valueType: [ Bounds2 ]
-    } );
-    this.availableModelBoundsProperty.link( bounds => {
-      model.availableModelBoundsProperty.set( bounds );
-    } );
-
     // @protected (read-only)
     this.skaterNode = new SkaterNode(
       model.skater,
Index: js/playground/view/EnergySkateParkPlaygroundScreenView.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/playground/view/EnergySkateParkPlaygroundScreenView.js b/js/playground/view/EnergySkateParkPlaygroundScreenView.js
--- a/js/playground/view/EnergySkateParkPlaygroundScreenView.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/playground/view/EnergySkateParkPlaygroundScreenView.js	(date 1611443758669)
@@ -84,7 +84,7 @@
    * @returns {TrackNode}
    */
   addTrackNode( track ) {
-    const trackNode = new TrackNode( this.model, track, this.modelViewTransform, this.availableModelBoundsProperty, this.trackNodeGroupTandem.createTandem( track.tandem.name ) );
+    const trackNode = this.trackNodeGroup.createNextElement( track, this.modelViewTransform, this.availableModelBoundsProperty );
     this.trackNodes.push( trackNode );
     this.trackLayer.addChild( trackNode );
 
Index: js/playground/model/EnergySkateParkPlaygroundModel.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/playground/model/EnergySkateParkPlaygroundModel.js b/js/playground/model/EnergySkateParkPlaygroundModel.js
--- a/js/playground/model/EnergySkateParkPlaygroundModel.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/playground/model/EnergySkateParkPlaygroundModel.js	(date 1611443745578)
@@ -10,7 +10,6 @@
 
 import merge from '../../../../phet-core/js/merge.js';
 import energySkatePark from '../../energySkatePark.js';
-import ControlPoint from '../../common/model/ControlPoint.js';
 import EnergySkateParkModel from '../../common/model/EnergySkateParkModel.js';
 import Track from '../../common/model/Track.js';
 
@@ -52,18 +51,17 @@
       trackOptions: null
     }, options );
 
-    const controlPointGroupTandem = this.controlPointGroupTandem;
-    const trackGroupTandem = this.trackGroupTandem;
-
     const controlPoints = [
-      new ControlPoint( -1, 0, merge( { tandem: controlPointGroupTandem.createNextTandem() }, options.controlPointOptions ) ),
-      new ControlPoint( 0, 0, merge( { tandem: controlPointGroupTandem.createNextTandem() }, options.controlPointOptions ) ),
-      new ControlPoint( 1, 0, merge( { tandem: controlPointGroupTandem.createNextTandem() }, options.controlPointOptions ) )
+      this.controlPointGroup.createNextElement( -1, 0, options.controlPointOptions ),
+      this.controlPointGroup.createNextElement( 0, 0, options.controlPointOptions ),
+      this.controlPointGroup.createNextElement( 1, 0, options.controlPointOptions )
     ];
 
-    return new Track( this, controlPoints, null, merge( {
-        tandem: trackGroupTandem.createNextTandem()
-      }, Track.FULLY_INTERACTIVE_OPTIONS, options.trackOptions )
+    return this.trackGroup.createNextElement( controlPoints, null, merge(
+      {},
+      Track.FULLY_INTERACTIVE_OPTIONS,
+      options.trackOptions
+      )
     );
   }
 
Index: js/common/model/EnergySkateParkTrackSetModel.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/model/EnergySkateParkTrackSetModel.js b/js/common/model/EnergySkateParkTrackSetModel.js
--- a/js/common/model/EnergySkateParkTrackSetModel.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/model/EnergySkateParkTrackSetModel.js	(date 1611442362804)
@@ -118,7 +118,7 @@
 
     this.trackTypes.forEach( trackType => {
       if ( trackType === PremadeTracks.TrackType.PARABOLA ) {
-        const parabolaControlPoints = PremadeTracks.createParabolaControlPoints( this.controlPointGroupTandem, options.parabolaControlPointOptions );
+        const parabolaControlPoints = PremadeTracks.createParabolaControlPoints( this,options.parabolaControlPointOptions );
         const parabolaTrack = EnergySkateParkTrackSetModel.createPremadeTrack( this, parabolaControlPoints, merge( {
           tandem: tandem.createTandem( 'parabolaTrack' )
         }, options.parabolaTrackOptions ) );
@@ -126,7 +126,7 @@
         tracks.push( parabolaTrack );
       }
       else if ( trackType === PremadeTracks.TrackType.SLOPE ) {
-        const slopeControlPoints = PremadeTracks.createSlopeControlPoints( this.controlPointGroupTandem, options.slopeControlPointOptions );
+        const slopeControlPoints = PremadeTracks.createSlopeControlPoints( this, options.slopeControlPointOptions );
         const slopeTrack = EnergySkateParkTrackSetModel.createPremadeTrack( this, slopeControlPoints, merge( {
 
           // Flag to indicate whether the skater transitions from the right edge of this track directly to the ground
@@ -137,14 +137,14 @@
         tracks.push( slopeTrack );
       }
       else if ( trackType === PremadeTracks.TrackType.DOUBLE_WELL ) {
-        const doubleWellControlPoints = PremadeTracks.createDoubleWellControlPoints( this.controlPointGroupTandem, options.doubleWellControlPointOptions );
+        const doubleWellControlPoints = PremadeTracks.createDoubleWellControlPoints( this, options.doubleWellControlPointOptions );
         const doubleWellTrack = EnergySkateParkTrackSetModel.createPremadeTrack( this, doubleWellControlPoints, merge( {
           tandem: tandem.createTandem( 'doubleWellTrack' )
         }, options.doubleWellTrackOptions ) );
         tracks.push( doubleWellTrack );
       }
       else if ( trackType === PremadeTracks.TrackType.LOOP ) {
-        const loopControlPoints = PremadeTracks.createLoopControlPoints( this.controlPointGroupTandem, options.loopControlPointOptions );
+        const loopControlPoints = PremadeTracks.createLoopControlPoints( this, options.loopControlPointOptions );
         const loopTrack = EnergySkateParkTrackSetModel.createPremadeTrack( this, loopControlPoints, merge( {
           draggable: this.tracksDraggable,
           tandem: tandem.createTandem( 'loopTrack' )
Index: js/common/model/EnergySkateParkModel.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/js/common/model/EnergySkateParkModel.js b/js/common/model/EnergySkateParkModel.js
--- a/js/common/model/EnergySkateParkModel.js	(revision 8b95f1ed3aa26c30f73757afe9d56d2d75f3933f)
+++ b/js/common/model/EnergySkateParkModel.js	(date 1611445427334)
@@ -39,6 +39,7 @@
 import merge from '../../../../phet-core/js/merge.js';
 import Stopwatch from '../../../../scenery-phet/js/Stopwatch.js';
 import TimeSpeed from '../../../../scenery-phet/js/TimeSpeed.js';
+import PhetioGroup from '../../../../tandem/js/PhetioGroup.js';
 import PhetioObject from '../../../../tandem/js/PhetioObject.js';
 import Tandem from '../../../../tandem/js/Tandem.js';
 import IOType from '../../../../tandem/js/types/IOType.js';
@@ -106,19 +107,41 @@
       skaterOptions: null
     }, options );
 
+    // @public - emits an event whenever a track changes in some way (control points dragged, track split apart,
+    // track dragged, track deleted or scene changed, etc...)
+    this.trackChangedEmitter = new Emitter();
+
     // @public (read-only)
     this.tracksDraggable = options.tracksDraggable;
     this.tracksConfigurable = options.tracksConfigurable;
     this.defaultFriction = options.defaultFriction;
 
-    const controlPointGroupTandem = tandem.createGroupTandem( 'controlPoint' );
-    const trackGroupTandem = tandem.createGroupTandem( 'track' );
+    // @public - Will be filled in by the view, used to prevent control points from moving outside the visible model
+    // bounds when adjusted, see #195
+    this.availableModelBoundsProperty = new Property( new Bounds2( 0, 0, 0, 0 ), {
+      tandem: tandem.createTandem( 'availableModelBoundsProperty' ),
+      phetioType: Property.PropertyIO( Bounds2.Bounds2IO )
+    } );
 
-    // @protected
-    this.controlPointGroupTandem = controlPointGroupTandem;
+    // @public {PhetioGroup.<ControlPoint>} group of control points
+    this.controlPointGroup = new PhetioGroup( ( tandem, x, y, options ) => {
+      assert && options && assert( !options.hasOwnProperty( 'tandem' ), 'tandem is managed by the PhetioGroup' );
+      return new ControlPoint( x, y, merge( {}, options, { tandem: tandem } ) );
+    }, [ 0, 0, {} ], {
+      tandem: tandem.createTandem( 'controlPointGroup' ),
+      phetioType: PhetioGroup.PhetioGroupIO( ControlPoint.ControlPointIO ),
+      phetioDynamicElementName: 'controlPoint'
+    } );
 
-    // @public
-    this.trackGroupTandem = trackGroupTandem;
+    // @public {PhetioGroup.<Track>} group of tracks
+    this.trackGroup = new PhetioGroup( ( tandem, controlPoints, parents, options ) => {
+      assert && options && assert( !options.hasOwnProperty( 'tandem' ), 'tandem is managed by the PhetioGroup' );
+      return new Track( this, controlPoints, parents, merge( {}, options, { tandem: tandem } ) );
+    }, [ [ this.controlPointGroup.createNextElement( 0, 0 ), this.controlPointGroup.createNextElement( 100, 0 ) ], [], {} ], {
+      tandem: tandem.createTandem( 'trackGroup' ),
+      phetioType: PhetioGroup.PhetioGroupIO( Track.TrackIO ),
+      phetioDynamicElementName: 'track'
+    } );
 
     // {boolean} - Temporary flag that keeps track of whether the track was changed in the step before the physics
     // update. True if the skater's track is being dragged by the user, so that energy conservation no longer applies.
@@ -206,13 +229,6 @@
       tandem: tandem.createTandem( 'stickingToTrackProperty' )
     } );
 
-    // @public - Will be filled in by the view, used to prevent control points from moving outside the visible model
-    // bounds when adjusted, see #195
-    this.availableModelBoundsProperty = new Property( new Bounds2( 0, 0, 0, 0 ), {
-      tandem: tandem.createTandem( 'availableModelBoundsProperty' ),
-      phetioType: Property.PropertyIO( Bounds2.Bounds2IO )
-    } );
-
     // @public {UserControlledPropertySet} - collection of Properties that indicate that a user is
     // modifying some variable that will change physical system and modify all saved energy data
     this.userControlledPropertySet = new UserControlledPropertySet();
@@ -259,10 +275,6 @@
       track.dispose();
     } );
 
-    // @public - emits an event whenever a track changes in some way (control points dragged, track split apart,
-    // track dragged, track deleted or scene changed, etc...)
-    this.trackChangedEmitter = new Emitter();
-
     // Determine when to show/hide the track edit buttons (cut track or delete control point)
     const updateTrackEditingButtonProperties = () => {
       let editEnabled = false;
@@ -290,7 +302,7 @@
     this.eventTimer = new EventTimer( new EventTimer.ConstantEventModel( FRAME_RATE ), this.constantStep.bind( this ) );
 
     if ( EnergySkateParkQueryParameters.testTrackIndex > 0 ) {
-      DebugTracks.init( this, tandem.createGroupTandem( 'debugTrackControlPoint' ), tandem.createGroupTandem( 'track' ) );
+      DebugTracks.init( this );
     }
   }
 
@@ -1544,15 +1556,12 @@
 
     track.removeEmitter.emit();
     this.tracks.remove( track );
-    const trackGroupTandem = this.trackGroupTandem;
 
     if ( track.controlPoints.length > 2 ) {
       const controlPointToDelete = track.controlPoints[ controlPointIndex ];
       const points = _.without( track.controlPoints, controlPointToDelete );
       controlPointToDelete.dispose();
-      const newTrack = new Track( this, points, track.getParentsOrSelf(), merge( {
-        tandem: trackGroupTandem.createNextTandem()
-      }, Track.FULLY_INTERACTIVE_OPTIONS ) );
+      const newTrack = this.trackGroup.createNextElement( points, track.getParentsOrSelf(), Track.FULLY_INTERACTIVE_OPTIONS );
       newTrack.physicalProperty.value = true;
       newTrack.droppedProperty.value = true;
 
@@ -1596,18 +1605,14 @@
     assert && assert( track.splittable, 'trying to split a track that is not splittable!' );
     const controlPointToSplit = track.controlPoints[ controlPointIndex ];
 
-    const trackGroupTandem = this.trackGroupTandem;
-
     const vector = Vector2.createPolar( 0.5, modelAngle );
-    const newPoint1 = new ControlPoint(
+    const newPoint1 = this.controlPointGroup.createNextElement(
       track.controlPoints[ controlPointIndex ].sourcePositionProperty.value.x - vector.x,
-      track.controlPoints[ controlPointIndex ].sourcePositionProperty.value.y - vector.y,
-      { tandem: this.controlPointGroupTandem.createNextTandem() }
+      track.controlPoints[ controlPointIndex ].sourcePositionProperty.value.y - vector.y
     );
-    const newPoint2 = new ControlPoint(
+    const newPoint2 = this.controlPointGroup.createNextElement(
       track.controlPoints[ controlPointIndex ].sourcePositionProperty.value.x + vector.x,
-      track.controlPoints[ controlPointIndex ].sourcePositionProperty.value.y + vector.y,
-      { tandem: this.controlPointGroupTandem.createNextTandem() }
+      track.controlPoints[ controlPointIndex ].sourcePositionProperty.value.y + vector.y
     );
 
     const points1 = track.controlPoints.slice( 0, controlPointIndex );
@@ -1616,14 +1621,10 @@
     points1.push( newPoint1 );
     points2.unshift( newPoint2 );
 
-    const newTrack1 = new Track( this, points1, track.getParentsOrSelf(), merge( {
-      tandem: trackGroupTandem.createNextTandem()
-    }, Track.FULLY_INTERACTIVE_OPTIONS ) );
+    const newTrack1 = this.trackGroup.createNextElement( points1, track.getParentsOrSelf(), Track.FULLY_INTERACTIVE_OPTIONS );
     newTrack1.physicalProperty.value = true;
     newTrack1.droppedProperty.value = true;
-    const newTrack2 = new Track( this, points2, track.getParentsOrSelf(), merge( {
-      tandem: trackGroupTandem.createNextTandem()
-    }, Track.FULLY_INTERACTIVE_OPTIONS ) );
+    const newTrack2 = this.trackGroup.createNextElement( points2, track.getParentsOrSelf(), Track.FULLY_INTERACTIVE_OPTIONS );
     newTrack2.physicalProperty.value = true;
     newTrack2.droppedProperty.value = true;
 
@@ -1669,27 +1670,25 @@
   joinTrackToTrack( a, b ) {
     const points = [];
     let i;
-    const controlPointGroupTandem = this.controlPointGroupTandem;
-    const trackGroupTandem = this.trackGroupTandem;
 
     const firstTrackForward = () => {
       for ( i = 0; i < a.controlPoints.length; i++ ) {
-        points.push( a.controlPoints[ i ].copy( controlPointGroupTandem.createNextTandem() ) );
+        points.push( a.controlPoints[ i ].copy( this ) );
       }
     };
     const firstTrackBackward = () => {
       for ( i = a.controlPoints.length - 1; i >= 0; i-- ) {
-        points.push( a.controlPoints[ i ].copy( controlPointGroupTandem.createNextTandem() ) );
+        points.push( a.controlPoints[ i ].copy( this ) );
       }
     };
     const secondTrackForward = () => {
       for ( i = 1; i < b.controlPoints.length; i++ ) {
-        points.push( b.controlPoints[ i ].copy( controlPointGroupTandem.createNextTandem() ) );
+        points.push( b.controlPoints[ i ].copy( this ) );
       }
     };
     const secondTrackBackward = () => {
       for ( i = b.controlPoints.length - 2; i >= 0; i-- ) {
-        points.push( b.controlPoints[ i ].copy( controlPointGroupTandem.createNextTandem() ) );
+        points.push( b.controlPoints[ i ].copy( this ) );
       }
     };
 
@@ -1718,21 +1717,19 @@
       secondTrackBackward();
     }
 
-    const newTrack = new Track( this, points, a.getParentsOrSelf().concat( b.getParentsOrSelf() ), merge( {
-      tandem: trackGroupTandem.createNextTandem()
-    }, Track.FULLY_INTERACTIVE_OPTIONS ) );
+    const newTrack = this.trackGroup.createNextElement( points, a.getParentsOrSelf().concat( b.getParentsOrSelf() ), Track.FULLY_INTERACTIVE_OPTIONS );
     newTrack.physicalProperty.value = true;
     newTrack.droppedProperty.value = true;
 
     a.disposeControlPoints();
     a.removeEmitter.emit();
-    if (this.tracks.includes(a)) {
+    if ( this.tracks.includes( a ) ) {
       this.tracks.remove( a );
     }
 
     b.disposeControlPoints();
     b.removeEmitter.emit();
-    if (this.tracks.includes(b)) {
+    if ( this.tracks.includes( b ) ) {
       this.tracks.remove( b );
     }
 
@@ -1866,15 +1863,15 @@
    * @param {Tandem} tandem
    * @param {boolean} draggable
    * @param {boolean} configurable
-   * @param [number[]} controlPointTandemIDs
+   * @param {number[]} controlPointTandemIDs
    */
   addTrack( tandem, draggable, configurable, controlPointTandemIDs ) {
 
     assert && assert( controlPointTandemIDs, 'controlPointTandemIDs should exist' );
     const controlPoints = controlPointTandemIDs.map( ( id, index ) => {
-      return new ControlPoint( index, 0, { tandem: Tandem.createFromPhetioID( id ) } ); // TODO: create with correct initial x & y values.
+      return this.controlPointGroup.createNextElement( index, 0, { tandem: Tandem.createFromPhetioID( id ) } ); // TODO: create with correct initial x & y values.
     } );
-    const newTrack = new Track( this, controlPoints, [], {
+    const newTrack = this.trackGroup.createNextElement( controlPoints, [], {
       draggable: draggable,
       configurable: configurable,
       tandem: tandem

samreid · 2021-01-24T04:37:56Z

I'll continue on Energy Skate Park in phetsims/energy-skate-park#123. But it revealed another deprecated method that should be eliminated as part of this issue: createFromPhetioID.

samreid · 2021-01-24T04:56:27Z

Summarizing work done in this issue:

Forbid '~' in Tandem names, and remove special handling for it.
Remove deprecated method createFromPhetioID
Remove clearChildInstances and addChildElementDeprecated
Addressed and eliminated all TODOs that referenced this issue
For the sims listed in the issue description, many parts just needed to be uninstrumented. Other cases used static indices.
Undeprecate GroupTandem for cases where indexed PhetioObjects are created statically. It is typically used like:

const plusChargesGroupTandem = tandem.createTandem('plusCharges').createGroupTandem( 'plusCharge' );
...
plusChargesGroupTandem.createNextTandem();

Energy Skate Park is using PhetioGroup but doesn't yet work in the state wrapper (but it also failed the state wrapper before any changes for this issue). That work will be done as part of Tracks and Control Points should use PhetioGroup energy-skate-park#123

@zepumph can you please review?

zepumph · 2021-01-28T23:14:01Z

This is some really great stuff. Thanks for taking the lead here. It's great to see this old pattern gone!

For the sims listed in the issue description, many parts just needed to be uninstrumented. Other cases used static indices.

For color vision I saw that you just uninstrumented but didn't replace. I noticed phetsims/color-vision#134, so I made a note there. Perhaps there are more like that but I didn't see.

I can't think of anything else here. Great work.

samreid · 2021-02-02T16:27:52Z

For color vision I saw that you just uninstrumented but didn't replace.

Yes, as described in #87 (comment):

For the sims listed in the issue description, many parts just needed to be uninstrumented. Other cases used static indices.

I also added a comment about color vision: phetsims/color-vision#134

It was unclear that the photons need to be instrumented, we can decide when we revisit this simulation for phet-io.

Thanks, closing.

chrisklus added the dev:phet-io label Apr 17, 2019

chrisklus assigned samreid, chrisklus and zepumph Apr 17, 2019

zepumph mentioned this issue Apr 17, 2019

Prevent "_" from appearing in non-group-member tandems #80

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chrisklus added a commit to phetsims/molecules-and-light that referenced this issue Nov 13, 2019

Add TODO for using PhetioGroup, see phetsims/tandem#87

ea84b05

zepumph changed the title ~~Remove Tandem.GroupTandem~~ Remove Tandem.GroupTandem and previous state pattern Nov 15, 2019

samreid mentioned this issue Dec 24, 2019

Use EnergySkateParkBasicsModel.addTrack more broadly phetsims/energy-skate-park#165

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This was referenced May 29, 2020

Use PhetioGroup phetsims/molecules-and-light#353

Closed

Use PhetioGroup phetsims/color-vision#134

Open

samreid added the priority:3-medium label Jun 12, 2020

samreid added a commit to phetsims/molecules-and-light that referenced this issue Sep 29, 2020

Move TODOs to another issue, see phetsims/tandem#87

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samreid added a commit to phetsims/energy-skate-park that referenced this issue Sep 29, 2020

Move TODOs to another issue, see phetsims/tandem#87

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samreid added a commit to phetsims/color-vision that referenced this issue Sep 29, 2020

Move TODOs to another issue, see phetsims/tandem#87

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samreid added a commit to phetsims/build-an-atom that referenced this issue Sep 29, 2020

Move TODOs to another issue, see phetsims/tandem#87

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samreid unassigned chrisklus Nov 24, 2020

samreid added a commit to phetsims/balloons-and-static-electricity that referenced this issue Dec 27, 2020

Fix typo, see phetsims/tandem#87

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samreid added a commit to phetsims/balloons-and-static-electricity that referenced this issue Dec 28, 2020

Fix typo, see phetsims/tandem#87

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This was referenced Jan 20, 2021

Remove Tandem.GroupTandem and previous state pattern phetsims/balloons-and-static-electricity#477

Closed

Remove Tandem.GroupTandem and previous state pattern phetsims/build-an-atom#221

Closed

samreid added a commit to phetsims/circuit-construction-kit-black-box-study that referenced this issue Jan 20, 2021

Opt out of instrumentation for black box wire stubs, see phetsims/tan…

f94a11e

…dem#87

samreid added a commit to phetsims/circuit-construction-kit-common that referenced this issue Jan 20, 2021

Opt out of instrumentation for CircuitStruct, see phetsims/tandem#87

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samreid added a commit to phetsims/friction that referenced this issue Jan 20, 2021

Format with idea code style, see phetsims/tandem#87

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samreid added a commit to phetsims/molarity that referenced this issue Jan 23, 2021

Uninstrument tick nodes, see phetsims/tandem#87

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samreid added a commit that referenced this issue Jan 23, 2021

Undeprecate GroupTandem, and omit ~ in the tandem string, see #87

1887e22

samreid added a commit to phetsims/ohms-law that referenced this issue Jan 23, 2021

Uninstrument dot nodes, see phetsims/tandem#87

a865a56

samreid added a commit to phetsims/balloons-and-static-electricity that referenced this issue Jan 23, 2021

Use GroupTandem, see phetsims/tandem#87

99a204f

samreid added a commit to phetsims/build-an-atom that referenced this issue Jan 23, 2021

Use GroupTandem, see phetsims/tandem#87

e1d6901

samreid added a commit to phetsims/shred that referenced this issue Jan 23, 2021

Use GroupTandem, see phetsims/tandem#87

ee83d74

samreid added a commit to phetsims/build-an-atom that referenced this issue Jan 23, 2021

Remove clearChildInstances and addChildElementDeprecated, see phetsim…

980e0ed

…s/tandem#87

samreid added a commit to phetsims/energy-skate-park that referenced this issue Jan 23, 2021

Remove clearChildInstances and addChildElementDeprecated, see phetsim…

8b95f1e

…s/tandem#87

samreid added a commit to phetsims/color-vision that referenced this issue Jan 23, 2021

Remove clearChildInstances and addChildElementDeprecated, see phetsim…

d43eea2

…s/tandem#87

samreid mentioned this issue Jan 24, 2021

Tracks and Control Points should use PhetioGroup phetsims/energy-skate-park#123

Closed

samreid added a commit to phetsims/energy-skate-park that referenced this issue Jan 24, 2021

Use PhetioGroup for control points and tracks, see phetsims/tandem#87

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samreid added a commit that referenced this issue Jan 24, 2021

Remove deprecated method createFromPhetioID, see #87

bb701b6

samreid added a commit to phetsims/energy-skate-park that referenced this issue Jan 24, 2021

Remove unused method, see phetsims/tandem#87

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samreid added a commit to phetsims/color-vision that referenced this issue Jan 24, 2021

Remove unused method, see phetsims/tandem#87

710cd36

samreid added a commit that referenced this issue Jan 24, 2021

Forbid '~` in Tandem names, see #87

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samreid removed their assignment Jan 24, 2021

samreid added the status:ready-for-review label Jan 24, 2021

zepumph assigned samreid and unassigned zepumph Jan 28, 2021

samreid added the type:epic label Feb 2, 2021

samreid closed this as completed Feb 2, 2021

zepumph mentioned this issue Feb 26, 2021

Wrapper Unit Tests: createTandem cannot accept dots, Property already deferred phetsims/energy-skate-park#68

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jessegreenberg pushed a commit to phetsims/greenhouse-effect that referenced this issue Apr 21, 2021

Add TODO for using PhetioGroup, see phetsims/tandem#87

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jessegreenberg pushed a commit to phetsims/greenhouse-effect that referenced this issue Apr 21, 2021

Move TODOs to another issue, see phetsims/tandem#87

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Remove Tandem.GroupTandem and previous state pattern #87

Remove Tandem.GroupTandem and previous state pattern #87

chrisklus commented Apr 17, 2019 •

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Remove Tandem.GroupTandem and previous state pattern #87

Remove Tandem.GroupTandem and previous state pattern #87

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