dsh-cad — CAD Plugin for DeepSeek Harness

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A CAD plugin for DeepSeek Harness (dsh): an embedded 3D/2D CAD viewer plus a native parametric modeling tool family (OCCT kernel) in the Web UI, letting the agent build and inspect CAD geometry step by step — "model while you watch".

Preview

A full modeling session, end to end: the agent builds a parametric assembly from plain chat — a 120×80×8 base plate with R5 rounded corners, then four bolt instances placed at the corners — while the resident CAD panel tracks every step live (parts tree with per-instance colors, ViewCube, "装配体" assembly tab, 5 instances · 1,740 triangles). The finished assembly exports as a structured STEP document and the agent verifies it by reading the file back — 2 solids, 3 products, 2 assembly usages, 1,125.00 mm³:

Feature Overview

Capability	Description
⚙️ Single-kernel architecture	occt.ts as the primary modeling kernel (true B-splines, native shell/draft, centroid); opencascade.js stays only as the fallback backend; the v0.8 "no editing after shell" seam is gone — fillet/chamfer/boolean keep working after shelling
🔍 CAD viewing	STL / OBJ / STEP / IGES / BREP / DCPRT (3D), DXF / SVG (2D); interactive in-chat card (orbit / zoom / wireframe / pan)
🧭 CAD editor interactions	Onshape-style ViewCube (26-zone click-to-orient), hover/click face & edge picking with live measurement (area mm² / length mm), Faces+Edges / Faces / Wireframe render modes, switchable BRep demo parts (bracket / flange / shaft)
🏗️ Parametric modeling	Primitives, profile extrusion, loft, sweep, revolve, booleans, all-edge fillet/chamfer, shell, draft, patterns (linear/circular), transforms; profiles take curve segments (arcs/circles exact BRep; B-splines sampled approximation) — exact OCCT BRep, not a mesh approximation
🗂️ Codex-style document tabs	The resident display panel gets a tab strip with a "+" menu: Part (Part Studio, the default) / Assembly (instance insert/move/remove) / Drawing (true hidden-line sheets); tabs are closable and keep their state
📁 Multi-document file space	Named documents per workspace (.dsh-cad/docs/), each session bound to its own active document — new sessions start empty instead of inheriting leftovers; a folder button in the panel lists every document (preview / delete), and cad_doc_new / cad_doc_open manage the modeling target from chat
📐 Engineering drawings	GB first-angle layout: front / top / left views + isometric, true OCCT hidden-line removal via the occt.ts kernel (an npm dependency, dashed); sheet frame, title block, overall dimensions, standard scale series; exports SVG / DXF
🔗 Constraint solving & motion	Ansatz geometric constraint solver (one command: npm install ansatz-wasm — a wasm dependency, no Rust toolchain, no native binary): entity/constraint modeling (assembly instances ↔ rigid3 poses mapped automatically), solve-with-writeback, full DOF/residual/redundancy/suggestion diagnostics (LLM-oriented), and parametric kinematic sweeps (cad_constraint / cad_solve / cad_motion)
📐 Geometry measurement	Exact volume (mm³), bounding box, triangle counts, DXF layers
📤 On-demand export	STEP (parametric) / STL (mesh); files are written only when the user asks
🖥️ Resident CAD panel	A permanent panel

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