Before decimation
Run checks for non-manifold edges, duplicate faces, floating fragments, inverted normals, and open boundaries. Clean these before reducing polygons; decimation can hide source problems and make them harder to diagnose.
Decimation tradeoffs
Decimation reduces triangle count but can destroy silhouette, bevels, UVs, and bake correspondence. Use stronger reduction on noisy flat scan areas and lighter reduction on edges, holes, sockets, screw threads, facial features, or contact surfaces. Preserve landmarks before running automatic reduction.
Watertight repair choices
For print, close every boundary and inspect wall thickness. For games, close only gaps that cause visible leaks, collision issues, or bake errors. For CAD conversions, remove internal faces and tiny sliver surfaces that add cost without visible value.
Validation after cleanup
Compare before/after silhouette, triangle count, open-edge count, non-manifold count, and UV/material survival. Import into the target engine or slicer; a mesh that passes in Blender may still fail a slicer wall-thickness test or engine collider generation.
Delivery note
Record source type, original triangle count, final triangle count, reduction method, protected areas, remaining intentional openings, and the validator used.
Multilingual production terms
| 中文 | English | 日本語 | Workflow usage note |
|---|---|---|---|
| 网格抽稀 | Mesh Decimation | メッシュ間引き | Use these terms when cleaning scanned, sculpted, or print-oriented meshes before reduction. |
| 水密网格 | Watertight Mesh | 水密メッシュ | Use these terms when cleaning scanned, sculpted, or print-oriented meshes before reduction. |
| 抽取 | Decimation | デシメーション | Use these terms when cleaning scanned, sculpted, or print-oriented meshes before reduction. |
| 网格清理 | Mesh Cleanup | メッシュクリーンアップ | Use these terms when cleaning scanned, sculpted, or print-oriented meshes before reduction. |
Term notes for multilingual briefs
Use the English term Watertight Mesh with matching Chinese/Japanese notes where relevant: 水密网格 / 網格削減 / メッシュクリーンアップ. Keep the technical term beside the local-language note so reviewers can map it back to DCC and engine settings.
Related pages and next step
FAQ
Does every game asset need to be watertight?
No. Watertight geometry is required for some workflows, but many game visual meshes can have intentional openings if they render and collide correctly.
Can I decimate before cleanup?
It is safer to remove non-manifold edges, floating parts, and inverted normals first. Decimation can spread defects.
What reduction percentage is safe?
There is no universal percentage. Use visual comparison and target platform budgets; protect silhouette and functional contact surfaces.
What proves cleanup worked?
Before/after counts, validator results, silhouette screenshots, and target import or slicer proof.
Worked review example
For a photogrammetry statue, first delete floating dust fragments and internal scan shells. Make the base watertight only if it will be printed, voxelized, or used for solid collision. Then decimate broad stone surfaces more aggressively than facial details, fingers, or chipped silhouette edges. Compare the final mesh under grazing light; decimation that looks acceptable in a front view can destroy edge character when the camera moves.