Okay, I'm working on a pair of shoes for Poser, modeled in Wings 3D. I export them as OBJ and import them into Poser, and they look like this:

I have the weird parts pointed out with red arrows. Does anyone know why Poser makes those strange shading spots, and what I can do to make it go away? They don't show up in Wings' smoothed view, and they show up in renders. They also show up in node-based textures; I haven't tried putting a JPEG texture map on them to see if that makes them go away (but at any rate, I'm not using texture maps on the finished shoes so I need them to work with node-based textures).

Could you post the wires? Looks like the mesh is pinching.

Laurie

Have you chosen a crease angle in Poser or did you just hope for the best?

If the areas in question are transitioning locally to being under the crease angle, but elsewhere it was over, then that would happen. Not the only possible reason - but a likely one.

What is a crease angle? I guess I didn't set one, in that case.

Here are a couple of wireframe pics. This one shows backfacing polygons, although I hid the sole of the shoe in an attempt at keeping it from being an indistinguishable mass of lines:

Here is one with backfacing polygons removed:

A crease is a shared polygon boundary, across which no smoothing is performed.

Poser defines a crease angle for each actor in properties. Edge angles below this angle are considered "smooth" and the renderer will attempt to simulate a continuous smooth surface, instead of a pair of flat polygons, passing through that edge. Edges above the crease angle are considered creases (tight folds) and smoothing doesn't happen.

In a long row of polygons if some are above the crease angle and some below, you'll get mysterious regions of sharp crease followed by no crease, even though to your eye they are nearly identical regions.

The default crease angle is 80 degrees.

Crease/smooth decisions are only made where adjacent polygons are welded by common vertices. If polygons are not welded, their joined edges are merely an illusion and are never smoothed out.

In the left side of the wireframe image it seems to be a not welded vertex or a degenerate quad, this can be the cause of the left side bump in the rendering.

In the right side I see nothing in the wireframe image, but it can be the same problem.

I also can see something similar more to the center of the wireframe, but in this case it produce no visible artifact in the rendering.

Check the mesh in detail to see if this problem do exist or are only my eyes

Thanks a million for the suggestions, everyone! I was about to give up on this project...

It turned out to be a crease-angle issue. I changed the crease angle from 80 to 95, added a few practically microscopic bevels to keep some edges sharp, and it works perfectly now.