GrblGru is a free CAM program for controlling milling machines, lathes, lasers, polystyrene cutters and other machines.

It calculates G-code, which is then translated into precise axis movements by a controller. GrblGru can also be directly connected to a controller via USB to take over the machine's control functions.

The entire workflow can be checked for functionality and collision avoidance in a graphical simulation. Over 80 different 3D machine models are available for this purpose, and these can also be expanded with custom models.

In addition, many other functions are provided, such as puzzle boxes, spur gears, oloids, QR codes, the slicer, and the macro language.