[FEATURE REQUEST] Align model horizontally by drawing reference lines

[RobLinkA]

Description:
Propose adding a new alignment tool that allows users to level models by drawing reference lines. Users can draw a line along any edge that should be horizontal (like building eaves or foundation), and the system will automatically calculate and apply the rotation needed to make that line level. Complete spatial alignment can be achieved by drawing reference lines from two perpendicular views.

Benefits:

1. More Intuitive Operation:

   • No need to manually set rotation pivot points
   • Direct visual feedback through line drawing
   • Similar to perspective correction in photo editing software

2. Higher Precision:

   • Eliminates the difficulty of precise control found in traditional rotation gizmos
   • System automatically calculates exact rotation angles
   • Reduces the need for manual fine-tuning

3. Improved Efficiency:

   • Complete leveling with just two line drawings
   • Significantly reduces time spent on iterative adjustments
   • Automatic calculation of optimal rotation

Suggested Implementation:

1. Add a "Line Alignment" button to the toolbar
2. When activated, allow users to drag and draw reference lines in the viewport
3. Automatically rotate the model to align the drawn line horizontally
4. Support repeated operations from perpendicular views for complete spatial alignment

Use Cases:

• Correcting photogrammetry-generated 3D models
• Adjusting scanned architectural models
• Quick alignment of tilted objects
• Any scenario requiring precise horizontal/vertical alignment

Technical Considerations:

• Tool should work in the current view perspective
• Rotation should maintain model's position while adjusting orientation
• Consider adding visual guides to help users identify perpendicular views

[kinedix]

Fully Support this feature request, one more solution to this will be select 3 points and make it planar rotation, in a lot of 3d tracking software this is common way. and add Distance between 2 points might be a great feature as well!