To open a space in the safe, you must first define the space as a polygon.
Click the Jump to Support / Object Points row (to be able to follow the dimensions).
Click on all objects around the boundaries of the polygon you will draw. The corner points of these objects have become active to jump.
Click on the Line Drawing / Polygon and draw the space you will create.
Click on the Modify / Transform / Polygon-> Space Transform line.
Click on the safe and then on the polygon.
A polygon-sized space has been opened inside your safe.
Click the Support / Delete Free Jump Points row to cancel the jump points.