# Text to CAD (parametric parts)

Ask Spark (Womp AI) for a measured part, change its sizes in the properties panel, and bake it into plain geometry.

**Use this when:** the thing you want has measurements, such as a bracket, case, tray, holder, frame, clip, stand or pot.

**Don't use this for:** organic or character shapes with nothing to measure. Read Images and 3D models.

Spark (Womp AI) can design a measured part from a description. It writes an OpenSCAD program, runs it, and puts the part in your scene. The key sizes become parameters you can change afterwards.

## What it needs

- **A project open.** If you start from the Spark page on a computer, Womp creates a project for you and opens it.
- **A computer.** Phones cannot open projects, so this is not offered there.
- **Spark credits.** Each design or change in the chat spends credits. While the offer runs, your first parametric part is free, and suggestions that use it show `Free to try`.

## Ask for a part

Pick the `Parametric part` chip in a new chat, or describe the part. Give sizes if you have them:

![The new chat in the Spark panel: What do you want to make? with the chips Image and 3D model, and Parametric part cut off below.](/docs/images/ui/text-to-cad-chips.webp)

*Pick `Parametric part` to ask Spark for a part with editable sizes.*

> Design a parametric drawer organizer tray 150 by 100 mm and 30 mm tall, divided into a 3 by 2 grid of compartments with 2 mm walls and lightly rounded inner corners.

Use the word "parametric" to make sure Spark designs a part instead of generating an image or building from shapes. If you leave out sizes, Spark picks sensible ones and exposes them so you can fix them.

## Change the part

- **Properties panel:** select the part. Its parameters appear on the right: widths, heights, wall thicknesses, hole counts and so on. Change a number and the part rebuilds. This does not use Spark.
- **Chat:** ask for changes the parameters do not cover, such as a new feature, a fillet or a new parameter. Spark edits the program and rebuilds. Each change spends credits.

You cannot open or type into the OpenSCAD code yourself. Ask Spark for the change.

## Bake it

The properties panel has a `Bake` button. Baking adds a frozen copy of the part to your scene as plain geometry, with no parameters. You can edit the copy like any other Womp object. The parametric part stays in the scene, so delete or hide the one you do not want before you export.

To download the part as a 3D file, see [Import and export](https://womp.com/docs/make/import-export.md).

## What works well

Parts made of boxes, cylinders, cones and tapers, rounded corners and fillets, turned profiles, and one shape repeated in a row or grid usually come out right the first time.

Dense patterns such as honeycombs, hexagon grids and interlocking tiles often come back wrong. Avoid them, or expect to ask again.

## Use instead

- **Wrong move:** asking for a parametric dragon or octopus. **Why:** there are no sizes to drive, so a parametric part does not fit. **Right move:** generate an image and make it 3D. See [Images and 3D models](https://womp.com/docs/make/spark-generations.md).
- **Wrong move:** asking Spark in the chat to make the part 10 mm taller. **Why:** that spends credits for a change the parameters already cover. **Right move:** select the part and change the number in the properties panel.
- **Wrong move:** ordering a print without checking wall thickness and clearances. **Why:** a part can be correct in size and still too thin to print. **Right move:** check [Walls and holes](https://womp.com/docs/print/walls-and-holes.md) and [Fits and clearances](https://womp.com/docs/print/fits-and-clearances.md).

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Last checked: 2026-11-09. Womp version: Womp web app, November 2026.