If you're in P5, have you got polygon smoothing on?

I've had the same problems with much simpler objects. And it has nothing to do with polygon smoothing. It has to do with the fact that Poser has no clue about Phong shading angles. Polygon smoothing is a panacea for this in Poser, but it doesn't always work (or works best on organic objects). Shading angles are sometimes a requirement for even planar features, especially with alternating triangles. I have a well modeled object in C4D which exhibits these render artifacts at standard 89% shading angle as well as 60% (my usual fix). As soon as it is set to 20%, perfection. With Poser, no matter what the setting used in UVMapper Pro to fix this (even 0%!!), artifacts occur. Umm, there is no easy way to do this in Poser. You may have to turn polygon smoothing off, to add edge bevels, rework the model, remove degenerate polygons, redundant vertices, split vertices in UVMapper, play with smoothing in UVMapper, guess, or pray. I spent an entire day importing an object into Poser with various "fixes" applied in UVMapper and Poser, but to no avail. It is not my model that is at fault, it is Poser. From my experience, Poser does not like long, thin polygons. The closer to inscribable within a square, the better. I don't know for certain, but no one has enlightened me to why this occurs and how to avoid it. Sometimes the fix is simple, other times it is impossible. I will not create/sell any more products for Poser until explanations that solve these idiosyncracies are given.

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.

One thing that I've just tried and discovered still to be true is that "quads good - triangles bad", especially for Poser. It seems that a quick way to avoid smoothing/shading errors is to use quads as much as possible and avoid triangles, especially triangle fans, at all costs. In my reasoning, triangles are the best approach to -modeling- since it is impossible to have a non-planar triangle in Cartesian geometry, ever. We won't speak of Euclidean geometry and its kin. In another reasoning, though, quads are better for texturing, lighting, and shading models. A quick perusal of some models and modeling tutorials shows this is the approach oft used - quads as much as possible. Would it were that modeling programs had a "quads only" mode, but most automatically create mesh geometry using triangles and quads, mostly of the former. Not all forms can be box modeled. This means hopeful editing after the fact...

(1) FireFly renderer with no smoothing. Production quality.

(2) P4 renderer of Poser 5.

We still have same problems.
It was not polygon smoothing as was suggested by kuroyume0161.

Thank you.
Himico