Here’s an example of the kind of 3D carvings which can be done on my CNC router:

This 3D object began life as a 2D drawing:

A bit of digital massaging transformed the 2D drawing above into a machinable 3D object. I used 2 pieces of totally free cross platform software, GIMP, and Blender3D to create the 3D object, to demonstrate that you don’t need software costing thousands of dollars to create something I can cut for you.

When it comes to creating the “G-code” that tells the machine exactly what to do and where, there isn’t really any good free software yet, so I use commercial software called  MeshCAM. In the picture below you can see the object loaded in MeshCAM, and ready to codes for the machine. It’s called an “STL” file, and it’s made up entirely of tiny triangles. Bazillions of them. The blue line in the center lets you know which way is up.

All those fine green lines show where the tip of the tool is going to go. This is called a “toolpath”. Typically a job like this will have at least two toolpaths, a “rough” cut and a “finish” cut. The close distance between the lines in the image above shows this is a finishing toolpath. The closer the lines, the finer the finish, and the more time it takes to complete.

The program was test cut first in insulation foam, since it’s cheap, easy on cutters, and cuts quickly. The finishing toolpath has smoothed out the area in the bottom half of the photo, while the ridges from the roughing toolpath are still visible in the top half.