I think object space normalmaps don't use the normals of the lowpoly at all just override them but tanget space works together with the lowpolys normals.
I believe smoothing groups are a term used in 3ds Max, right? Maybe I should have mentioned what program I am working in, I'm working in Maya. And I believe all polygons are smoothed the same but with hard edges where I have UV-splits.. :/ Maybe I could remove the cutouts in my lowpoly, that's true, and that might be my…
Well it's supposed to look like that. The shading and "ugly edges" are there to compensate for the smoothing on your lowpoly. The question is whether the normalmap does its job or not. If the model looks alright with the normalmap applied then there's no problem. If it doesn't then it'll be easier to help if you post some…
it kinda looks like you don't have proper smoothing groups set (in this case some of the triangles in your mesh having a completely different smoothing group altough they are basicly in the same "plane" with some minor differences). So if possible put a screenshot of your lowpoly (without wires and normal map) Also, why…