Hey all, I've been experimenting with Poser figures in max for a while, and I noticed this weird issue today.
I imported a fairly simple model into max, via Poserfusion, just a v4 with a T-shirt, jeans, boots and hair (a simple hair mesh). Import went fine, and the materials were summed up in only 4 multi-sub slots. Rendering went smoothly too. Then, I converted the entire scene to VRay and rendered. All went well here too. Saved and went to sleep.
Today I opened up the scene and re-rendered, changing none of the settings I made yesterday, but all of a sudden v4's skin, hair and T-shirt had the weirdest colors. Played around with the settings, checking if something changed accidentaly, but it was all just as I left it. Then I noticed that it wasn't the shaders, but the UV coordinates themselves that had gone mad, and what I had was the teeth map all over the shirt, the hair or tongue map all over the skin, and maybe a few other mixes as well.
The strange thing is that the jeans and (I think) the shoes where fine. I had imported the jeans material from the scene library into an empty material slot to change the reflection values, so I suspect that this somehow may have stabilized the jeans' UVs. Crazy, but I can't think of anything else.
Has anyone else here experienced something similar? Is there some way to prevent the UV maps from abandoning their assigned body parts?

More important perhaps, is there a new PoserFusion coming out anytime soon? A hopefully more stable version that can cooperate with other programs without forcing the user to pull his hair off?!
 

I'm not quite sure what you mean when say "converted the entire scene to VRay".

After assign VRay as renderer, I just convert certain materials to VRay types (like those with reflection or refraction) and leave rest as standard material.  IMHO, there is not much advantage in converting simple material like cloth to VRay material.

If you are using some maxscript to convert materials, I would suspect some problem there. 

Any time I use some script that affects materials, I always select renderer first because syntax and offset sometime different in each engine.

  Thank you for the advice, this may be just what's wrong. However, it doesn't explain why I get the UV error after I reload my scene and not right after I convert it, but I suppose that's too much to ask for :)

I don't know which version of VRay you're using, but VRay 1.5 SP2 gives you the option to convert the entire scene into VRay, which pretty much converts the textures, and possibly optimizes/precalculates the models in order to render faster or more efficiently with VRay.
You just have to right click in an empty area of your viewport and select that option from the list.
Perhaps there are other versions of VRay that have this option, but I only know about the one I use.

I thank you for information on scene convertor.  I didn't know it came with VRay, I thought it was something I had downloaded from somewhere and forgot.  Mainly because it never worked right.  Now, I go to see what stopping it and see that converter not understand "Strauss" method, so I change to "Blinn" and it converts all the way through.  It doesn't handle certain transparencies for me, like the EyeSurface so I fix manually.  For hair, I think Standard material with Strauss is better than VRay with Blinn.

I cannot duplicate the problem you are having with my own system (Max9 with VRay 1.47), so I don't know where it comes from.

I have duplicated problem now.  The reason not see before is that I pinned a UnWrap UVW modifier to figure.  If you unpin it, it goes crazy when you reopen scene in new session.

To work around, add unwrap modifier to figure, then convert with VRay converter.  You can leave it on because it should not bother anything

 A million thanks, I'll try this solution as soon as I return home. By the way, when I import a model with PoserFusion, that model usually divides in 4 (or more) separate meshes. I suppose I must apply Unwrap to every one of them, correct?
And thank your for the tip on the figure's hair as well, I hardly ever used Strauss, and this is very interesting.
If the problem gets solved, I will also try playing with VRay SSS material, to see if the skin will trully improve.

Each figure (i.e., clothing, hair) is a separate mesh.  I did not notice it so much in clothing, mainly I think because they are tiled box mapped and not overlaid pelt map like figure of V4.

 Thanks for that info. Just yesterday I experienced the same issue. It appeared to me that the issue involved material IDs that got switched or replaced. I didn't try to troubleshoot it but I recall I did have an UnWrap modifier on a couple of objects in the scene so I'll look there per your findings.