Hi, I usually use the pathfinder to combine objects to a single vector for laser cutting as in Object - Group. Effect - Pathfinder - Add. Object - Expand Appearance.
This has worked for me upto now but it has always been adding a shape to the outside of another shape then combining them.
I want to add a shape to the inside of another shape and then combine them but when I try this the shape inside the other shape disappears.
Any help would be much appreciated.