This cut out will be routed in your PCB during manufacturing.
Generally these details are provided in Drill drwaing layer but you can ask you fabrictor about this , as how it needs the detail provided in the PCB.
Ah, that's what I thought. A make a mechanical layer and place the outlines of the cut out routing there.
And at the output files I can detail the depth of the routing or can this be done on the mechanical layer?
Yes it can be done on mechanical layer also but better to do it in drill drawing layer as it is the layer that contain all other drill details.
You can also provide cut out details in both layers i.e. mecahnical and drill drawing.
I will once again suggest you to consult your fabricator, that how he wants cutout details, so it is easy for it to undersatnd what exactly you need.
Good tool but it is not applicable for complex shapes, especially inside of board.
Another method exists.
I create a drawing of PCB with all cutouts in Solid Works and export it to STEP model. Then, do Design-> Board Shape -> Define from 3D body and select your step file. Try it and you will appreciate the result.