decimate_qem — 3D `mesh_process` op

• 資料種類:mesh → mesh

• 呼叫: import fullseye as fs; fs.ledger.decimate_qem(V, F, target_faces, protect=None)(要直接呼叫實作,import meshrepair; meshrepair.decimate_qem(V, F, target_faces, protect=None);從台帳取用則 ops3d.get("decimate_qem"))

用法

面向 *target_faces* 的二次誤差度量(QEM)邊塌陷簡化。

> 以下的詳細說明為原文 —— 摘要與標題已翻譯。

*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.

背景知識指南(該運算子背後的物理與規範)

• blender_interop — Blender との併用 — 形を作って fullseye で測る(軸・単位・正解データの罠)

參考(範例資料・文獻)

• 範例資料目錄(下載 URL / 授權) —— 2-D 用 skimage.data(BSD/公有領域)加合成圖,3-D 給出真實資料源(Stanford/PDS 等)的下載 URL。

• 運算子來歷與參考文獻 —— 該運算子族所依據的研究/方法出處。

可執行的範例(實際呼叫該運算子並已驗證的樣例)

• 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

型別可銜接的下一個運算子(可接受 `mesh` 作為輸入)

mesh_to_voxel · mesh_to_points · to_points · fuse_to_voxel · ambient_occlusion · cast_shadow · supersample_mesh · render_beauty

同類別(`mesh_process`)

laplacian_smooth · taubin_smooth · face_normals · vertex_normals · mesh_area · vertex_curvature · face_areas · mesh_volume

*Provenance: meshrepair.py — 3D 運算子登記表。本條目由 tools/opdocs.py md 自動產生(請勿手動編輯)。*

decimate_qem — 3D mesh_process op

用法