Turbosmooth ruins Unwrap

Medusa · Aug 2012

Hello,

I modeled a fire hydrant and I'm having some trouble texturing it. I unwrapped the lowpoly version, but when I import the hipoly model into mudbox to paint over it, the turbosmooth creates errors along the seams. In some parts the edges even overlap because of this smoothing. What is the best option for dealing with this problem?

I attached 2 images showing the lowpoly and the hipoly versions of the UVW, so that you can see what I mean.

Thank you!

McGreed · Aug 2012

Usually you don't unwrap the highpoly, and when you do, they don't match the lowpoly at all. Just unwrap the highpoly as you want, it can be completely different, because you bake the details FROM the highpoly TO the lowpoly. Think you might have misunderstood how to make highpoly models to use for lowpoly.

Medusa · Aug 2012

Thank you McGreed for your reply. But to make things clear, I want to make the highpoly model look as good as possible, there will be no lowpoly version. I wanted to import the Turbosmoothed version of the object in Mudbox and paint over it. But because I unwrapped only the lowpoly object, and not the highpoly, this created problems where the seams are. So I wonder if I should add another UVWUnwrap over the Turbosmooth in 3DSMax and relax all the seam edges?

I also tryed copying the Channel Info from below the Turbosmooth on top of it, but that didn't worked very well either

hiredblade · Aug 2012

Wait, you left pentagons on the low poly. That would make some of the distortion.
remember, quads and tris are always better than n-gons for subdivision.

However, distortions on the seams are a bit strange. What about checking smoothing groups?

McGreed · Aug 2012

I don't understand what you mean with seams, but if you mean the edged edge of your circles, it should be easy to fix, just select all the UVs and apply some relax on them, that should do the trick.

Medusa · Aug 2012

Thank you hiredblade, but that's not what's causing the issue here. The problem is caused by the Turbosmooth modifier, which makes everything rounder, except for the seam edges in the UV layout. Is it a good idea to have an unwrap of the highpoly model, in order to paint over it? Or is there a better idea for texturing highpoly objects?

Medusa · Aug 2012

Ok McGreed, that's what I'm talking about and I thought about doing that. I was just wondering if there's a better option, so that I don't have to always work twice on the unwrap. And also, If I do this, I won't be able to later modify the Turbosmooth without having to retouch the unwrap again.

respawnrt · Aug 2012

http://www.neilblevins.com/cg_tools/cg_wishlist/3dsmax/wishlist_linear_uvs_in_turbosmooth.htm
http://3dsmaxfeedback.autodesk.com/forums/80695-publicgeneralfeaturerequests/suggestions/1472239-smoothing-uv-s

joeriv · Aug 2012

Edit: oh, seems that it is possible from the links that respawnrt posted :poly136:

Ignore my post, except for when it still doesn't work

Sometimes you can get away with unwrapping the low poly (or in this case basicly the control mesh for the HP), but it's never gonna be perfect.

I got away with it on my car, because I was able to hide it in between the seems of the door/etc, and adding some extra edges along the borders so those wouldn't "stretch" so far.

But in this case, you will have to unwrap the highpoly.

If you want to do it in a alternate way without having to resort to unwrapping, and if you are working in max (probably also works in other programs, but never done that in there).

You can basicly just work with the max materials.
For example for an asset like this (wich is purely for the highpoly/presentation, not ingame purposes).

You could make a material, like you always do, maybe add some rust/dirt by using some tricks with AO maps, and blending materials together.

And then afterwards, let's say you want it more beat up, make a rust material, vertex paint that in.

And except for maybe some cases (certain maps that do require UV coordinates) you shouldn't have to unwrap.

Downside is that you basicly have to dive into/learn max material creation, and everything and making use of all the options you have there.

Medusa · Aug 2012

respawnrt: Thank you very much for the link, I'll give it a try.

joeriv: Haha, too late! I read it already :P Thank you, I understand what you're saying. First I'll try what respawnrt said and see how it works. I wanted to unwrap the model and texture it like that for learning purposes. Almost always I've worked around that, but I think it's time for me to learn texturing like this too

anaho · Aug 2012

If you just want to texture the Hipoly, you have to unwrap it with a sub-d modifier applied. Usually if your render settings are set to two iterations it is enough to apply a sub-d of level one and unwrap this. You can also delete unneccesarry edge loops after you have applied it.

Medusa · Aug 2012

Thank you, anaho. So I guess in the end unwrapping the highpoly is the best option? I was trying to unwrap it with two iterations, but it makes better sense what you're saying and it's also a bit faster.

hiredblade · Aug 2012

With the links provided by respawnrt it turns out to be an incompatibility between max and mudbox. And as you said, its probably the best solution to unwrap the highpoly.

You probably figured out this part. Just to take note as result of the thread.

anaho · Aug 2012

Well idealy you would unwrap at the render level sub-d. However, it is very clumsy to deal with that much vertices when doing unwrapping. I always apply a first iteration of sub-d and do an unwrap on this in Blender and think that this will work in most applications alike. I think ( not sure) you could only depend on the "lopoly" unwrap if you are using Pixar-style subdivisions that for example Modo supports. Not sure, though.

Medusa · Aug 2012

hiredblade: Yeah, probably unwrapping the highpoly is the best option in this case.

anaho: I applied the Unwrap over the Turbosmooth with one iteraion and started relaxing the edges. It's not that difficult like this, it just gets a bit boring after a while

. But the important thing is that it works, thanks for the idea.

Medusa · Aug 2012

So I think I've decided which one's the best solution for this: unwrap the unsmoothed version of the object, then collapse and add Turbosmooth with 1 iteration. After the Turbosmooth I added another UVWUnwrap and relaxed the edges that caused problems. In some parts 1 iteration wasn't enough, so I added another one and then relaxed again the faulty vertices in the UVW layout. Works like a charm now, no texture stretching whatsoever. Thank you everyone for your help

OccultMonk · Aug 2012

3Dsmax does not really support non-smoothing of UVW's when using turbosmooth. Zbrush for instance has a special setting to prevent UVW's from smoothing when dividing the geometry.

There are two options to prevent the UVW's from smoothing in 3DSmax:

1) Break all the polygons by selecting all edges and choosing break in the UVW editor. When you use turbosmooth the UVW's won't be smoothed.
2) Use Meshsmooth modifiers (with the 'Old Style Mapping' option checked) instead of Turbosmooth.

Turbosmooth ruins Unwrap

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