Hi Pluto,
Glad to hear PixelCNC is doing what you hoped for! You can use the Profile Milling operation from the 2D/2.5D Milling operations category to cut around a shape that's on the canvas, or use a paths-layer as contour input to the operation. The "Simple Relief Cut-Out" tutorial will walk you though what goes into cutting a 3D shape and then cutting it out with the profile milling operation :]
Just as a heads up: we're having some server issues at the moment so the Content Library and automatic updates may be offline for a few days, until Monday at the latest but hopefully we'll resolve the issue sooner. We'll get it squared away ASAP.
Let me know if you have any other questions or need help with anything else!
- Charlie