How to predict possible interference by planning a piece modeled in sheet metal.
Can anyone give me some tips to eliminate these interferences future?
Without knowing exactly what you are after - one way to avoid troubles is to ask sheet metal fabricator if what you intend to design is doable at all.
Well, that add on is for pressed sheet metal parts. Inventor off the shelf doesn't have such capabilities.
As for the picture I have to get my head around of what is it?