@petrence said:
here are the pictures of my molding pattern, what i'd like to remake with sketchup. this also has a negative. any ideas how do i need really exact opposite side with the same dimensions? i think this will be the next difficult step for me.
Think you are looking for a mirror image. Use the scale tool and scale at -1. If you first do a copy , then the mirror and then paste in place you have the two.