Autodesk · sebastienblor · Sep 13, 2024 · Sep 13, 2024
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -38,6 +38,7 @@
 - [usd#2082](https://github.com/Autodesk/arnold-usd/issues/2082) - Support arnold cameras in hydra
 - [usd#2084](https://github.com/Autodesk/arnold-usd/issues/2084) - Imagers should be applied to all drivers
 - [usd#2086](https://github.com/Autodesk/arnold-usd/issues/2086) - Compute FOV in the procedural and hydra in a similar manner
+- [usd#2099](https://github.com/Autodesk/arnold-usd/issues/2099) - Ignore UsdGeom doubleSided parameter, which was setting geometries as single-sided by default
 
 ### Bug fixes
 - [usd#1961](https://github.com/Autodesk/arnold-usd/issues/1961) - Random curves width in Hydra when radius primvars are authored

diff --git a/libs/render_delegate/rprim.h b/libs/render_delegate/rprim.h
@@ -106,7 +106,7 @@ class HdArnoldRprim : public HydraType {
 
         if (checkSidedness && HdChangeTracker::IsDoubleSidedDirty(*dirtyBits, id)) {
             param.Interrupt();
-            const auto doubleSided = sceneDelegate->GetDoubleSided(id);
+            const auto doubleSided = true; //sceneDelegate->GetDoubleSided(id);
             _sidednessFlags.SetHydraFlag(doubleSided ? AI_RAY_ALL : AI_RAY_SUBSURFACE);
             AiNodeSetByte(GetArnoldNode(), str::sidedness, _sidednessFlags.Compose());
         }

diff --git a/libs/render_delegate/utils.cpp b/libs/render_delegate/utils.cpp
@@ -57,6 +57,7 @@ PXR_NAMESPACE_OPEN_SCOPE
 // clang-format off
 TF_DEFINE_PRIVATE_TOKENS(_tokens,
     ((arnoldVisibility, "arnold:visibility"))
+    ((arnoldSidedness, "arnold:sidedness"))
     ((visibilityPrefix, "visibility:"))
     ((sidednessPrefix, "sidedness:"))
     ((autobumpVisibilityPrefix, "autobump_visibility:"))
@@ -317,6 +318,16 @@ bool ConvertPrimvarToRayFlag(AtNode* node, const TfToken& name, const VtValue& v
         visibility->SetPrimvarFlag(visibilityValue, true);
         return true;
     }
+    if (sidedness && name == _tokens->arnoldSidedness) {
+        uint8_t sidednessValue = VtValueGetInt(value);
+        AiNodeSetByte(node, str::sidedness, sidednessValue);
+        // In this case we want to force the visibility to be this current value.
+        // So we first need to remove any visibility flag, and then we set the new one
+        sidedness->SetPrimvarFlag(AI_RAY_ALL, false);
+        sidedness->SetPrimvarFlag(sidednessValue, true);
+        return true;
+    }
+
     const auto* paramName = name.GetText() + str::t_arnold_prefix.size();    
     // We are checking if it's a visibility flag in form of
     // primvars:arnold:visibility:xyz where xyz is a name of a ray type.

diff --git a/libs/render_delegate/volume.cpp b/libs/render_delegate/volume.cpp
@@ -238,7 +238,7 @@ void HdArnoldVolume::Sync(
 
     if (HdChangeTracker::IsDoubleSidedDirty(*dirtyBits, id)) {
         param.Interrupt();
-        const auto doubleSided = sceneDelegate->GetDoubleSided(id);
+        const auto doubleSided = true; //sceneDelegate->GetDoubleSided(id);
         _sidednessFlags.SetHydraFlag(doubleSided ? AI_RAY_ALL : AI_RAY_SUBSURFACE);
         const auto sidedness = _sidednessFlags.Compose();
         _ForEachVolume([&](HdArnoldShape* s) { AiNodeSetByte(s->GetShape(), str::sidedness, sidedness); });

diff --git a/libs/translator/reader/read_geometry.cpp b/libs/translator/reader/read_geometry.cpp
@@ -160,12 +160,13 @@ static inline bool _ReadPointsAndVelocities(const UsdGeomPointBased &geom, AtNod
 static inline void _ReadSidedness(UsdGeomGprim &geom, AtNode *node, float frame) 
 {
     VtValue value;
-    if (geom.GetDoubleSidedAttr().Get(&value, frame) && VtValueGetBool(value))
+    if (true /*geom.GetDoubleSidedAttr().Get(&value, frame) && VtValueGetBool(value)*/)
         AiNodeSetByte(node, str::sidedness, AI_RAY_ALL);
     else {
         // USD defaults to single sided mesh.
         AiNodeSetByte(node, str::sidedness, AI_RAY_SUBSURFACE);
     }
+
 }
 
 void ReadMeshLight(const UsdPrim &prim, UsdArnoldReaderContext &context, AtNode *node, const TimeSettings &time) {

diff --git a/testsuite/test_0016/ref/reference.log b/testsuite/test_0016/ref/reference.log
diff --git a/testsuite/test_0016/ref/reference.tif b/testsuite/test_0016/ref/reference.tif
diff --git a/testsuite/test_0017/ref/reference.log b/testsuite/test_0017/ref/reference.log
diff --git a/testsuite/test_0017/ref/reference.tif b/testsuite/test_0017/ref/reference.tif
diff --git a/testsuite/test_0026/data/scene.usda b/testsuite/test_0026/data/scene.usda
@@ -41,7 +41,7 @@ def Xform "root" (
         float2[] primvars:st = [(0.0, 0.0), (1.0, 0.0), (0.0, 1.0), (1.0, 1.0)] (
             interpolation = "faceVarying"
         )
-
+        int primvars:arnold:sidedness = 0
         int[] primvars:st:indices = [0, 1, 3, 2, 0, 1, 3, 2]
     }
 

diff --git a/testsuite/test_0035/ref/reference.log b/testsuite/test_0035/ref/reference.log
diff --git a/testsuite/test_0035/ref/reference.tif b/testsuite/test_0035/ref/reference.tif
diff --git a/testsuite/test_0131/ref/reference.log b/testsuite/test_0131/ref/reference.log
diff --git a/testsuite/test_0131/ref/reference.tif b/testsuite/test_0131/ref/reference.tif
diff --git a/testsuite/test_0157/ref/reference.log b/testsuite/test_0157/ref/reference.log
diff --git a/testsuite/test_0157/ref/reference.tif b/testsuite/test_0157/ref/reference.tif
diff --git a/testsuite/test_0217/ref/reference.log b/testsuite/test_0217/ref/reference.log
diff --git a/testsuite/test_0217/ref/reference.tif b/testsuite/test_0217/ref/reference.tif
diff --git a/testsuite/test_0221/ref/reference.log b/testsuite/test_0221/ref/reference.log
diff --git a/testsuite/test_0221/ref/reference.tif b/testsuite/test_0221/ref/reference.tif
diff --git a/testsuite/test_0222/ref/reference.log b/testsuite/test_0222/ref/reference.log
diff --git a/testsuite/test_0222/ref/reference.tif b/testsuite/test_0222/ref/reference.tif
diff --git a/testsuite/test_0229/ref/reference.log b/testsuite/test_0229/ref/reference.log
diff --git a/testsuite/test_0229/ref/reference.tif b/testsuite/test_0229/ref/reference.tif
diff --git a/testsuite/test_0237/ref/reference.log b/testsuite/test_0237/ref/reference.log
diff --git a/testsuite/test_0237/ref/reference.tif b/testsuite/test_0237/ref/reference.tif
diff --git a/testsuite/test_0243/ref/reference.log b/testsuite/test_0243/ref/reference.log
diff --git a/testsuite/test_0243/ref/reference.tif b/testsuite/test_0243/ref/reference.tif
diff --git a/testsuite/test_0316/ref/reference.log b/testsuite/test_0316/ref/reference.log
diff --git a/testsuite/test_0316/ref/reference.tif b/testsuite/test_0316/ref/reference.tif
diff --git a/testsuite/test_1331/ref/reference.log b/testsuite/test_1331/ref/reference.log
diff --git a/testsuite/test_1331/ref/reference.tif b/testsuite/test_1331/ref/reference.tif
diff --git a/testsuite/test_1352/ref/reference.tif b/testsuite/test_1352/ref/reference.tif
diff --git a/testsuite/test_1420/ref/reference.log b/testsuite/test_1420/ref/reference.log
diff --git a/testsuite/test_1420/ref/reference.tif b/testsuite/test_1420/ref/reference.tif
diff --git a/testsuite/test_1468.2/ref/reference.log b/testsuite/test_1468.2/ref/reference.log
diff --git a/testsuite/test_1468.2/ref/reference.tif b/testsuite/test_1468.2/ref/reference.tif
diff --git a/testsuite/test_1718/ref/reference.log b/testsuite/test_1718/ref/reference.log
diff --git a/testsuite/test_1718/ref/reference.tif b/testsuite/test_1718/ref/reference.tif
diff --git a/testsuite/test_1735/ref/reference.tif b/testsuite/test_1735/ref/reference.tif
diff --git a/testsuite/test_1837/ref/reference.tif b/testsuite/test_1837/ref/reference.tif