# Overview
URL: /docs/kernels

# CAD Kernels Overview

Tau supports multiple CAD kernels. Specify the kernel when initializing the CAD machine or by loading an example that is tagged with the corresponding language.

| Kernel    | `kernelType` | Language flag        | Notes                                                           |
| --------- | ------------ | -------------------- | --------------------------------------------------------------- |
| Replicad  | `"replicad"` | `replicad` (default) | Parametric TS/JS API backed by OpenCascade.js.                  |
| OpenSCAD  | `"openscad"` | `openscad`           | WebAssembly build of OpenSCAD. Accepts standard `.scad` syntax. |
| Zoo (KCL) | `"zoo"`      | `zoo`                | KittyCAD Language for cloud-native CAD with AI integration.     |

## Current Limitations

### OpenSCAD

* Only STL generation is wired; STEP export is a TODO.
* Error messages are raw stderr text.

### Zoo (KCL)

* Requires internet connection for Zoo API access.
* API token required for full functionality.

Contributions welcome!
