Reverse CAD CAM

Hello. I have a client that needs a small machine to inject material
instead of removing it. Basically the machine will behave like a small
mill, but it will not take chips off, it will inject foam (I think).
The idea is to create objects in an empty space (no mold is present).
The client will provide the 3D objects, so I was wondering what are
the software that could take the 3D format (any popular format), and
output ISO gcode for the machine to handle.
Thank you from your time.

Filipe