A game engine & spatial agent layer

3D work that
proves itself.

Vellum is a full game engine — and a spatial agent layer for robotics, engineering and modeling. It builds the 3D work — scenes, shaders, CAD parts, kinematic rigs — then proves each result against real constraints: compiles, watertight, in tolerance, collision-free. The proof is renderer-neutral and runs headless on the CPU. No GPU in the loop.

speaks glTF · USDSTEPURDFThree.jsUnrealBlender

The proof runs on the CPU — the same verdict on a laptop, a CI runner, or a render farm.

scroll ↓
01gamescenes, shaders, levels
02roboticsrigs, reach, collision
03engineeringparts, tolerance, CAD
04modelingmeshes, splats, USD
one spatial kernel · renderer-neutral · headless by default
Renderer-neutral proof

It doesn't just make 3D. It proves it.

Most tools generate geometry and hand you a pretty render to eyeball. Vellum generates the work and then runs it through a verifier — a chain of spatial assertions that either pass or fail. Pick an artifact and watch the proof run: it loads, checks the geometry, measures against a target, and returns a verdict. Every check runs on the CPU, so there's nothing to eyeball and nothing to trust on faith.

01WriteGenerate the geometry or shader.
02LoadTessellate to a neutral mesh.
03AssertWatertight, manifold, in tolerance.
04MeasureScore against a real target.
05RenderHeadless raster — no GPU.
06VerdictPass, fail, with the receipts.
Before / after

See the proof, not a screenshot.

When the work is a shader or a look, Vellum writes several candidates, compiles each one, and scores them on what they actually output — not a vibe. The winner is the one that passed every assertion. Drag the slider to compare the rejected candidate with the selected one; the panel shows exactly why one won. No graphics card touched this.

ShadersCompile, render headless, score the look.
CAD partsWatertight, manifold, in tolerance, printable.
Game scenesCollision, navmesh, an automated playtest.
Splats & cloudsInspect and verify point-cloud captures.
A full game engine

Not just a verifier — the whole engine.

Vellum is a complete editor: a scene graph, physics, lighting and a play mode, with the agent and the proof built in. Lay out a level, press play, and it runs an automated playtest on the CPU — pathing the navmesh, checking collision, reaching the goal — and reports the same renderer-neutral verdict you get everywhere else. Hit play.

authoringScene graph, ECS, prefabs and a real-time viewport.
runtimePhysics, navmesh and play mode — deterministic on CPU.
shippingExport to Three.js, Unreal or Blender when it passes.
How a proof runs

From a prompt to a provable result.

Every job follows the same path. Vellum can attempt a task several ways in isolation, prove each attempt the same way, and keep only the candidate that clears the bar — then hand you the verdict and the numbers behind it.

01

Describe

“A printable bracket that holds 2 kg, under 60 g.” Plain language in, a spatial task out.

02

Generate

The agent writes the part, the shader or the scene — often several candidates at once.

03

Prove

Each candidate is loaded, asserted, rendered headless and measured against the target.

04

Keep

The winner is the one that passed — returned with its proof, not a promise.

headlessRenders on the CPU — runs anywhere, including CI.
deterministicSame input, same verdict, every time.
auditableEvery assertion and number is logged.
Renderer-neutral

One proof.
Every renderer.

Vellum's verdict doesn't depend on a renderer, a driver, or a graphics card. It reads and writes the formats you already use, and proves the work against a neutral spec — so a part that's watertight in Vellum is watertight in Blender, and a scene that passes here passes in Unreal. Bring the engine; keep the proof.

glTF / GLBread · writescenes & meshes
OpenUSDread · writelayered scenes
STEP / BREPread · tessellateCAD parts
URDF / SDFread · simulaterobot rigs
Three.js · Unreal · Blenderexportyour engine
vellum · headless
vellum prove bracket.step --target hold=2kg,mass<60g
load STEP → mesh · 18,402 tris (cpu)
assert watertight manifold tol ±0.05
fea max stress 0.62 · yield 1.0
render headless raster · 6 views no gpu
# nothing left a CPU core
verdict VERIFIED · mass 54.1 g · score 0.96
Built for trust

Nothing ships on a vibe.

Vellum keeps a running record of every assertion, measurement and render as it works — so you can see why a result was kept, what each candidate scored, and what it would do in your engine, without rerunning anything on a GPU.

Proven before it's kept

Every result clears geometry, tolerance, collision and a headless render before it counts.

Reads your assets

Points it at your scene or part and it understands the geometry — meshes, BREP, point clouds.

Targets, not vibes

Give it a number — mass, clearance, frame budget — and it proves the work hits it.

No GPU required

The whole verifier runs on CPU, so it works the same on a laptop or a headless CI box.

Fits your pipeline

Reads and writes glTF, USD, STEP and URDF — drop it between the tools you already use.

Deterministic proof

The same input gives the same verdict — every run, every machine, every time.

Best-of-N, judged

Attempts a task several ways in isolation and keeps the one that actually passes.

Headless by default

CPU proof runs the same on a laptop, a CI runner, or a render farm.

How it's built

A spatial kernel and an agent core.

A CPU spatial kernel does the geometry and the headless rendering; a separate agent core decides what to build and how to prove it. One stable contract joins them — each part runs offline, predictable and testable.

The spatial kernel · CPU
Scene graph & ECSEntities, components and a live scene tree.
Mesh & BREP coreLoads, tessellates and repairs geometry.
Physics & collisionRigid bodies, contacts and swept checks.
Assertion engineWatertight, manifold, tolerance, reach.
Headless rasterizerRenders views and play-tests with no GPU.
Format I/OglTF, USD, STEP, URDF in one neutral model.
The agent core
Spatial plannerTurns a goal into a buildable task.
GeneratorsWrites shaders, parts, rigs and scenes.
Best-of-NSeveral attempts, isolated and judged.
Verifier loopBuild, prove, measure, keep the winner.
Model providersLocal and cloud, behind one interface.
Proof ledgerLogs every assertion and number.
Ways to run it
Editor + play modeScenes, the viewport, play-test and proofs.
CLI · vellum proveProve an asset from the terminal.
CI gateBlock a merge until the 3D passes.
Engine pluginsThree.js, Unreal and Blender bridges.
Headless serviceProve assets on a render farm.
Eval harnessTrack solve-rate as models change.
Pricing

One subscription. Both apps.

Vellum's editor, engine and proof kernel are free to run locally — no account needed. A single Ephemerent subscription unlocks cloud agents in Vellum and the Orrery IDE together: same sign-in, same bundled DeepSeek models, one shared monthly token quota metered server-side.

Free

$0 forever
  • Full local editor, engine and play mode
  • Renderer-neutral proof kernel, CLI and CI gate
  • Local agent runs with deterministic tools
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$100 /month
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Ultra

$200 /month
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Renderer-neutral · headless proof

Stop eyeballing 3D.
Start proving it.

Point Vellum at a part, a shader, or a scene — get a verdict with the receipts.