> ## Documentation Index
> Fetch the complete documentation index at: https://invariant-cad.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Manifold backend

> Use the bundled watertight mesh runtime in Node.js and browsers.

Manifold is the default InvariantCAD backend. InvariantCAD bundles the pinned
standalone Manifold 3.5.1 core JavaScript and WebAssembly runtime, without its
unrelated glTF/image toolchain.

## Create directly

```ts theme={"system"}
import { createEvaluator, createManifoldKernel } from "invariantcad";

const kernel = await createManifoldKernel();
const evaluator = await createEvaluator({ kernel });
```

Calling `createEvaluator()` without a `kernel` performs the same selection.

## Custom WASM URL

```ts theme={"system"}
const evaluator = await createEvaluator({
  manifold: {
    wasmUrl: new URL("/static/manifold.wasm", location.href).href,
  },
});
```

The runtime is initialized once per JavaScript realm. The first URL becomes the
configured location. A later call with a different explicit URL fails because
two incompatible global module instances would make ownership unclear.

## Capabilities

The 0.1 adapter supports:

* box, cylinder/cone, and sphere primitives
* extrude and revolve
* union, subtraction, and intersection
* translation, rotation, scale, and mirror
* twist/top-scale extrusion
* mesh extraction, native measurements, and exact per-component mesh genus
* binary/ASCII STL and OBJ through shared exporters

It does not advertise exact B-Rep, native STEP/BREP, semantic topology
snapshots, exact fillets/chamfers/shells/offsets, lofts, or path sweeps.

## Precision model

Manifold computes robust solids internally, but its public mesh carries
Float32 vertex positions. Measurement methods call native Manifold volume,
surface-area, bounding-box, and tolerance functions and combine those with
bounded mesh integration for tensor properties. Genus is evaluated on every
fresh component returned by `decompose()`, validated as a nonnegative safe
integer, safe-summed, and cleaned up transactionally. That claim is exact for
the Manifold mesh representation, not an assertion about a source B-Rep.

A public mesh round-trip is not a lossless native shape codec. InvariantCAD
therefore does not advertise shape-artifact persistence for Manifold 3.5.1.

## Resource ownership

Each adapter shape wraps a native Manifold object. Feature intermediates and
evaluated output shapes are deleted by the owning evaluation. Disposing the
kernel releases any remaining live adapter shapes. The initialized Manifold
module promise remains cached for the lifetime of the JavaScript realm.

## Security and provenance

The bundled runtime bytes are pinned by SHA-256, verified during every build,
and shipped with Manifold and embedded-component license notices. This avoids
installing Manifold's optional glTF/image dependency graph in consumers while
preserving the exact tested core runtime. See [third-party notices](https://github.com/shlokjain42/invariantCAD/blob/main/THIRD_PARTY_NOTICES.md).