Fix for MultiPolygon errors and missing UV coordinates

[Janky2Slow]

Problem

The current Meshery implementation crashes when processing complex golf courses (18+ holes) with the error:

AttributeError: 'MultiPolygon' object has no attribute 'exterior'

Additionally, exported OBJ files don't include UV coordinates, making textures unusable in Unity.

Solution

I've fixed both issues:

1. MultiPolygon Handling (mesh.py)

• Added MultiPolygon support to densify_polygon() and triangulate_polygon()
• Functions now handle both simple Polygons and MultiPolygons
• Complex courses with hundreds of overlapping shapes now process correctly

2. UV Coordinate Generation (export.py)

• Added UV coordinate generation for all vertices
• Uses planar projection from XZ coordinates
• Exports proper vt lines in OBJ format
• Textures now work in Unity

Testing

Tested successfully with:

• Bartow18: 18-hole course with 165 paths - previously crashed, now works ✅
• Keystone12: 12-hole course with complex terrain - processes correctly ✅
• Simple courses continue to work without changes ✅

Files

I'll attach the two fixed files:

• mesh.py - MultiPolygon handling
• export.py - UV coordinate generation

Both files are backward compatible. No breaking changes.

mesh.py

export.py