mesh_process op• Data kinds: mesh → mesh
• Call: import fullseye as fs; fs.ledger.decimate_qem(V, F, target_faces, protect=None) (to call the implementation directly, import meshrepair; meshrepair.decimate_qem(V, F, target_faces, protect=None); from the registry, ops3d.get("decimate_qem"))
Quadric-error-metric edge-collapse decimation toward *target_faces*.
*protect* (optional, (nv,) bool): vertices that must survive untouched — no edge incident to a protected vertex is collapsed, so the faces around a crater rim, a boulder or any region you flagged keep their exact geometry (meshres.mesh_decimate_preserving derives the mask from the detail map and reports what the rest of the reduction lost).
Garland & Heckbert 1997: each vertex carries the sum of the squared-distance quadrics of its incident face planes; the cheapest edge is collapsed to the position minimising that quadric (a midpoint/endpoint fallback when the 3x3 system is singular, e.g. on a flat face), quadrics are accumulated onto the surviving vertex, and incident edge costs are re-queued. Collapses that would flip a face normal or land on a non-manifold edge are skipped, so the result stays a sane surface.
Honest scope: this is a practical QEM, not production-grade. It has no boundary-preservation term, no attribute (colour/UV) quadrics and no aggressive validity recovery, so on awkward meshes a few non-ideal collapses can survive and the collapse may stop a little short of *target_faces* when every remaining candidate is blocked by the flip/manifold guard. Good enough for a cheap collision proxy; not a replacement for a dedicated remesher.
• blender_interop — Using Blender alongside — build the shape, measure it with fullseye (pitfalls: axes, units, ground truth)
• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).
• Operator provenance and references — the sources of the research/methods this op family came from.
• mesh_decimate — py -3.11 examples_3d/mesh_decimate.py
• mesh_lod_download — py -3.11 examples_3d/mesh_lod_download.py
• mesh_resolution_demo — py -3.11 examples_3d/mesh_resolution_demo.py
mesh as input)mesh_to_voxel · mesh_to_points · to_points · fuse_to_voxel · ambient_occlusion · cast_shadow · supersample_mesh · render_beauty
mesh_process)laplacian_smooth · taubin_smooth · face_normals · vertex_normals · mesh_area · vertex_curvature · face_areas · mesh_volume
*Provenance: meshrepair.py — 3D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.