When a 3D model’s opacity stretches at nodes, it’s typically caused by distorted UV mapping or uneven vertex weight distribution for transparency.
- **UV Mapping Issues**: UVs link 2D opacity textures to 3D surfaces—if they’re misaligned or stretched, transparency distortion follows at nodes. - **Vertex Weight Problems**: Weights (for shaders/deformation) that don’t match the model’s geometry can make opaque/transparent areas pull abnormally at node points.
To fix it, use a UV unwrapping tool with auto-stretch correction or test a basic transparency shader to isolate the cause (UVs, weights, or shader complexity).