Shapeways' 3D printers can handle models with up to 1 million polygons. Tools like ZBrush, however, can easily generate high-polygon models that exceed this limit. Fortunately, polygon reduction (or mesh decimation) is a simple solution to this issue. Many 3D applications come with polygon reduction tools built in, but if yours doesn't, MeshLab is a powerful and free alternative. Available for Windows, macOS, and Linux, MeshLab can help reduce polygon count without sacrificing too much quality.
You can download Meshlab here.
For example, in a test using a toy car model with 480,000 faces, the polygon count was reduced to 120,000 faces with negligible quality loss. When the count dropped further, the model began to lose detail.
How to Use MeshLab for Polygon Reduction:
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Download and Install MeshLab: Start by installing MeshLab and importing your 3D model.
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Select the Simplification Filter:
- From the top menu, go to Filters > Remeshing, Simplification, and Construction > Quadratic Edge Collapse Decimation.
- If your model has textures, select the "with texture" option to ensure your textures remain intact.
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Optimal Settings for Polygon Reduction:
- Target number of faces: Keep this under 1 million to meet Shapeways' limit.
- Quality threshold: Set to 1. This controls how closely the new model will resemble the original. Higher values result in less simplification and better shape preservation.
- Preserve Boundary of the Mesh: Set to Yes to prevent boundary distortions (important for non-watertight models).
- Preserve Normal: Set to Yes to prevent normal flipping and preserve surface orientation.
- Optimal position of simplified vertices: Set to Yes for more accurate vertex positioning during edge collapse.
- Planar simplification: Set to Yes if your model contains flat surfaces. This ensures the geometry stays smooth.
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Handling Normal Inversions: If you notice any issues with inverted normals after upload, you can reorient them using Filters > Normals, Curvature and Orientation > Re-Orient all faces coherently.
By following these steps, you'll reduce the polygon count of your model while maintaining its quality and ensuring it meets Shapeways' upload requirements.