Quick start

Switch to the Katydid workbench. The canvas opens as a floating window over FreeCAD. If you closed it, use Katydid  Canvas or the canvas button on the Katydid toolbar.

Katydid works on the active document. If no document is open it creates one, because the preview needs a 3D view.

Double-click an empty spot on the canvas. A search box appears under the cursor.

Type slider, then press Enter. A Number Slider appears where you double-clicked.

Double-click the slider’s dark name label. The slider editor opens:

Set Name to Size, Minimum to 5, Maximum to 40, Value to 20, and click OK.

Double-click empty canvas again, type box and press Enter to place a Center Box. Its inputs X, Y and Z are on the left, its output B on the right.

The box already shows a 10 × 10 × 10 preview in the 3D view, because every input has a default value.

Press on the slider’s output grip (the small circle on its right edge) and drag onto the Box’s X grip. Release. A wire appears and the box takes the slider’s value for X.

Do the same from the slider to Y and to Z. One output can feed any number of inputs.

Drag the slider’s diamond along its rail. The box in the 3D view grows and shrinks as you drag.

The status line at the top right of the canvas shows how many components were recomputed and how long the solve and the preview took.

The red preview is not part of your document yet. Click Bake on the canvas toolbar: the box is added to the document as an ordinary FreeCAD object (a Part::Feature), which you can use with any other workbench. Bake adds everything previewed, or only the selected components if any are selected. Ctrl+Z in FreeCAD undoes a bake in one step.

Save the FreeCAD file as usual with Ctrl+S. The canvas is stored inside it, on a small Katydid object you can see in the model tree. Close and reopen the file: the canvas comes back exactly as you left it. Double-click the Katydid object to bring the canvas up if it is hidden. See Saving and files for details.