1. Final file format - .GLB (with Embedded textures).
  2. Model size:
    1. The final file size should be less than 40MB.
    2. The optimal size is 15MB
  3. Polygons count.
    1. Very important for app performance.
    2. Optimal - 100k, Maximum - any, but better less than 500k.
    3. The app can work even with more than 1M polygons but could cause poor performance on some devices.
  4. For best performance better to keep all textures in size of 1024x1024 px. **2k textures are ok but don’t use bigger than that. Keep them in the “Power of 2” (512x512, 1024x1024 and so on).

General 3D Model Requirements and best practices by Geenee: