Tvashtraत्वष्टृ
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Tvashtra · Misc42 Labs

LLM-driven CAD,
that doesn’t lie.

त्वष्टृ

The model builds the part. Sees the part. Fixes its own mistakes before it dares to call it done.

Desktop CAD on a real B-rep kernel (OCCT), not a toy mesh. You type intent. It runs solid-modeling ops. Four canonical views auto-render after every batch so the model checks its own work and retries when wrong. STL, STEP, OBJ go out the back. Your API key, your machine.

Join the betaSee the tour
The Tvashtra desktop shell — devanagari brand glyph, history rail on the left, six render modes above the viewport, and a chat composer on the right with sample prompts.
Desktop · OCCT · wgpu PBRForge Black

Why this exists

Two failure modes. One fix.

Most CAD tools fight you.

Constraints, menus, decade-old toolbars. A circle takes six clicks. A fillet is a tutorial.

Most LLM-CAD tools lie to you.

They emit code, declare success, render nothing, miss the hole, the chamfer is on the wrong edge, you only notice when it ships.

Tvashtra does neither.

B-rep kernel runs the op. Renderer captures four views. Model sees its own work. If wrong, it retries before answering you.

Without verification

A wireframe view that reveals the hole the model claimed it drilled isn't actually there — only an outline that looks right from one angle.
Model says “done.” The hole isn’t there. You only find out when you slice for print.

With closed-loop feedback

The same part rendered with the verified shaded mode — the hole is real, the fillets are real, the geometry matches what the model claims.
After each tool batch, Tvashtra renders four views (iso, front, top, right) and feeds them back. The model reads its own geometry. Wrong → it retries. Right → it tells you.

How it works

Four loops, not four hundred menus.

Talk → build → see → keep. The closed loop is the whole product.

01 · Talk

Type the intent.

A chat panel, not a ribbon. “Make a chess pawn 40mm tall via sketch and revolve.” “Fillet the top four edges by 2mm.” “Export as STEP.”

02 · Build

Real B-rep, not a toy.

OCCT under the hood. Primitives, booleans, sketch + extrude + revolve, fillet, chamfer, shell, pattern, transforms. STL / STEP / OBJ out the back.

03 · See

Four views, every batch.

After each tool call, the renderer captures iso + front + top + right. The model receives those images and verifies its own work before answering you.

04 · Keep

Your part. Your formats.

Local file. Open in Fusion / SolidWorks / Prusa / Blender. The transcript is your parametric history — fork from any prompt to branch the design.

Anatomy

Eleven regions, each doing one thing well.

The shell is the product. Every pixel of chrome was put there intentionally; nothing is decorative. Hover a number to read what it owns.

Labelled diagram of the Tvashtra desktop shell with eleven numbered regions.
  1. 01

    Brand mark

    Devanagari त्वष्टृ glyph in copper plus the Tvashtra wordmark. Doubles as a window-drag region.

  2. 02

    File actions

    New, Open, Save, Export · Undo / Redo. Ctrl-keyed shortcuts share the exact same handlers.

  3. 03

    Op counter

    Live count of operations in the current document. Reads from the kernel history, not the UI tree.

  4. 04

    Workspace toggles

    Stress, Inspector, Settings. Toggles fold panels in and out of the viewport overlay.

  5. 05

    History rail

    Parametric op tree. Click a node to pin the Inspector; branch from any ancestor to fork the design.

  6. 06

    Camera presets

    Top · Front · Right · Iso. Snaps the camera to a canonical view with smooth easing.

  7. 07

    Render modes

    Six modes: shaded, shaded+edges, wireframe, hidden-line-removed, hidden-line-dashed, sketch.

  8. 08

    Viewport

    wgpu PBR canvas with HDR image-based lighting from a Poly Haven studio environment.

  9. 09

    Chat composer

    Type intent in natural language; the model picks ops from the catalog and runs them against the kernel.

  10. 10

    Provider picker

    Claude, GPT, Gemini, or local llama.cpp. Your API key, your machine — nothing routed through us.

  11. 11

    Camera readout

    Live yaw / pitch / distance. Useful for replaying camera positions across screenshots and shares.

Tour

Six render modes, same geometry.

Studio IBL with real fillets.

Shaded

Studio IBL with real fillets.

PBR through wgpu with image-based lighting baked from a Poly Haven studio HDR. The fillets are real B-rep edges, not screen-space tricks.

Engineering look, kept legible.

Shaded + edges

Engineering look, kept legible.

MRT pass writes normal + depth alongside colour; the second pass runs Sobel for an outline overlay you can read across the whole part.

Topology at a glance.

Wireframe

Topology at a glance.

Every edge, no shading. Useful when you need to confirm a chamfer landed exactly where you think it did — or when the boolean tessellation looks suspicious.

Clean engineering drawing.

Hidden-line removed

Clean engineering drawing.

Front-facing edges only — the look a draftsperson would put on paper. Useful for screenshots in a spec doc or a part-fab brief.

Occluded edges, dashed.

Hidden-line dashed

Occluded edges, dashed.

The full drafting convention. Visible edges solid, hidden edges dashed. The B-rep edge graph drives this directly — no faking with shaders.

Presentation-ready clay.

Sketch

Presentation-ready clay.

Flat clay fill, bold contour. The mode you ship a render to a client in when the geometry is the story and the material isn't.

Install

Linux first. macOS & Windows in the pipeline.

Linux · paste, hit Enter

curl -fsSL https://misc42.github.io/tvashtra-landing/install.sh | bash

install.sh ↗

macOS

Universal2 .dmg (Intel + Apple Silicon) building in CI. Unsigned on first release — right-click → Open to bypass Gatekeeper.

Track on releases →

Windows

x64 .msi installer building in CI. Unsigned on first release — SmartScreen warning expected; click “More info” → “Run anyway.”

Track on releases →

Want a heads-up?

One mail when the macOS / Windows builds land. No newsletter apparatus.

Try in browser · coming soon

Tvashtra,
in your browser.

No install. Your API key. Your geometry.

Honest timeline

Kernel-to-WASM port is real engineering.

OCCT is ~2M lines of C++. A clean WASM build with tessellation, booleans, and STEP IO is 3–8 weeks of work depending on the path we take. We’ll ship it when it works, not before. Bring your own Gemini / Claude / OpenAI key — nothing routes through us.

  • · BYO API key (Anthropic / Gemini / OpenAI / Ollama)
  • · No backend, no account, no telemetry
  • · Export STL / STEP / OBJ directly from the tab

FAQ

Honest answers.

Why not Fusion / SolidWorks / OpenSCAD?
Those tools want you to drive every click. Tvashtra is LLM-native — the chat transcript becomes parametric history, and you can fork your part from any prompt. The kernel underneath is the same calibre (OCCT) as the open-source CAD lineage.
Does it use my GPU?
Yes — wgpu drives the viewport (RTX 4070, Apple Silicon, AMD, Intel Arc). The LLM runs on the provider's hardware (Anthropic / Google / OpenAI). If you want everything local, wire Ollama as the provider and run on your own card.
Do I need an API key?
Yes. Anthropic, Gemini, or OpenAI — or a local Ollama daemon. Your key, your spend, your privacy. Tvashtra never sees your traffic.
Does my data leak?
If you use a cloud LLM, that provider sees your prompts (Tvashtra doesn't proxy them — they go from your machine to the model). Local Ollama keeps everything on-box. No telemetry from Tvashtra either way.
What ops are supported today?
Primitives (box, cylinder, sphere, cone, torus), booleans (union, cut, intersect), sketch + extrude + revolve, fillet, chamfer, shell, pattern (linear + circular), transforms (translate, rotate, scale, mirror). Loft + sweep land in Phase 2.
Open source?
AGPL-3.0-or-later. Source is private during beta, public at v1. The landing page (this repo) is already public.