How to create a custom holder in Mastercam?

Step-by-step guide

In Mastercam in the top plane draw the shape of your holder like bellow (see this example Custom_holder.mcx-9 )
Go in the Tool Manager or directly in a path tool tab
Right click on your tool and edit holder
You can import or export the geometry in a level by clicking on the icons bellow:

Mastercam needs to recognized simple segments (build with simples lines). Complex geometries (splines, lots of brokens lines) might not work.