By the looks, it is caused by Poser's smoothing engine, which is not as capable as other apps... For sharp edges, Poser needs to have several steps around the edge in order to avoid bad shading. Also, it apears as though there as sections which have been split from other to avoid smoothing across them..this will work, unless you have a bend around one of those areas, then you will see the mismatched shading (as near the lights in the picture). For a vehicle to look good in poser, it needs a fairly heavy geometry. Thats why the vehicles in my store are so large.