Turbosmooth distorting UV edges?

Become a member of the CGSociety

Connect, Share, and Learn with our Large Growing CG Art Community. It's Free!

THREAD CLOSED
 
Thread Tools Search this Thread Display Modes
Old 04 April 2013   #1
Turbosmooth distorting UV edges?

I am working on a model that I take frequently between 3dsm and Zbrush. Pictures at bottom.

My workflow is as follows:

1) Create low poly base mesh in 3dsm.

2) Using smoothing groups and turbosmoothing I subdivide the whole model without losing the overall shape by using smoothing groups.

3) Take the turbosmoothed model into Zbrush where I can subdivide even further without losing the form/shape. If I would take the low poly mesh into Zbrush and subdivide it there I would get very bad results since I couldn't keep the shape like I can with smoothing groups. Technically I could do it with extra geometry, but that is something I'm avoiding.

4) Sculpt details in Zbrush and bake out normals and apply to the low poly in 3dsm.

This method has worked pretty well except for a minor issue. Basically, when I apply Turbosmooth, the seams of some of my UV islands get distorted. Those distorted UVS then get taken into Zbrush and baked onto. So when I apply the normal map to my low poly, the distortions are very obvious since the UVS of the low poly have not been distorted by Turbosmooth.



Here you can see the subdivided UV map on the left gets curved edges while the unsubdivided has straight edges.


Here you can see the distortion inside the red circles.



I did google the issue and found multiple threads about it, including ones from cgtalk like this however none of the solutions listed there work. Except the one about adding more geometry but that I'd prefer not to do, same with adding a UV unwrap modifier on TOP of the Turbosmooth because then I could not use my normal maps on my low poly model.

I did try splitting all edges, copying the Channel info, and pasting after disabling the edit poly where the splitting occured. No luck.

Most of the threads I found are at least 1-2 years old so I was wondering if there are some common workarounds for this issue?

Thanks.

edit: Ofcourse I "found" a way to fix the issue somewhat a few minutes after posting this thread. Detaching the affected polygons to element seems to minimize the problem. Although it has not completely disappeared.

However I'm not sure if that might cause other issues along the way, for example when I've taken it to Zbrush and start doing normal bakes since now many parts of the object are seperate geometry.

I'm still interested in hearing more solutions to this or if I'm doing something terribly wrong. Also some others might be having similar issues and this might be helpful.
Attached Images
File Type: png uvs.png (95.2 KB, 208 views)
File Type: png turbosmooth.png (78.9 KB, 201 views)

Last edited by l3ftnut : 04 April 2013 at 08:47 PM.
 
Old 04 April 2013   #2
Take the low poly mesh into zbrush and turn off the smooth modifier (smt button) before you subdivide. Or use the crease function which is like zbrush smoothing groups.
 
Old 04 April 2013   #3
Hi,

I don't know how "dense" your 3D object is, but what I do is to add a turbosmooth with 1 iteration, then add a UV wrap above it, unwrap it correctly, and then add another turbosmooth (with the iterations you need). You won't have problems with your uvs this way.

Sometimes the "meshsmooth" modifier works too, you have to check the "old mapping style" option, but this isn't working everytime (most of time it isn't )
 
Old 04 April 2013   #4
Originally Posted by Miniminer: Hi,

I don't know how "dense" your 3D object is, but what I do is to add a turbosmooth with 1 iteration, then add a UV wrap above it, unwrap it correctly, and then add another turbosmooth (with the iterations you need). You won't have problems with your uvs this way.

Sometimes the "meshsmooth" modifier works too, you have to check the "old mapping style" option, but this isn't working everytime (most of time it isn't )


I think the OP's end result is a low poly game-type mesh so will not be a turbosmoothed asset. At least that's what I got from the description.
 
Old 04 April 2013   #5
While you're at it, take a break and vote here at user voice:

http://3dsmaxfeedback.autodesk.com/...faces?ref=title

So we can fix this turbosmooth problem ONCE AND FOR ALL!
 
Old 04 April 2013   #6
Originally Posted by davius: While you're at it, take a break and vote here at user voice:

http://3dsmaxfeedback.autodesk.com/...faces?ref=title

So we can fix this turbosmooth problem ONCE AND FOR ALL!


Neil Blevins has been banging that particular drum for a LONG time without success.

And if they won't listen to him.....
 
Old 04 April 2013   #7
Think this plugin addresses some of the issues as well :
http://mariussilaghi.com/products/turbosmooth-pro

don't let this put you off voting for it in the user voice as well though.
__________________
Renderfarm hire available @ www.hotknife.co.uk
 
Old 04 April 2013   #8
Originally Posted by musashidan: Neil Blevins has been banging that particular drum for a LONG time without success.

And if they won't listen to him.....


That's true! Neil is a strong advocate of this (and LOTS more essential features) missing/bugged/incompatible feature of 3dsMax. At least it's "under review", although I don't know for how long and if it will result in any real implementation.

If only AD managers said "hey, you know what? I had this incredible idea - let's do the top 5 most voted features (plus the 9th feature 'cause it's UVs related ) of the Max uservoice, fix some bugs in the freetime and call it a new version!" Instant rush to buy new Max from all over the world!

If only...
 
Old 04 April 2013   #9
Originally Posted by hotknife: Think this plugin addresses some of the issues as well :
http://mariussilaghi.com/products/turbosmooth-pro

don't let this put you off voting for it in the user voice as well though.


Yes, I have tried TS Pro and it does bring Max up to date with the other 3D apps but why, oh why couldn't Adesk have implemented it this time round? All the work has already been done by Marius. Just pop it into the bloody modifier list!!
 
Old 04 April 2013   #10
Thanks for the replies guys! I appreciate them.

Hotknife, thank you for the plugin. I will test it out this evening, I'll update my post with the results.

Thanks for the link as well Davius! Found some of your posts on the issue when I was googling for solutions, some of those posts and threads are 5 years old if not older.

Hopefully Autodesk will fix this soon, although I find it highly unlikely seeing how old some of those posts/threads were..


Musashidan:

Thanks for the replies and yes, you're right. The model is supposed to be a in-game model, so I can't unwrap a tesselated model.

There are a few reasons for why I didn't disable the "smt" button or simply use creasing. I'll post pictures.

Here is the low poly model:



----

Here it is subdivided a few times with the "SMT" disabled, as you can see the nose causes issues:



----

Here I disabled SMT only on the first subdivision and enabled it for the 2nd and 3rd etc:



----

Here is the creased model, although I guess I could place some more creases by hand by hiding certain polygons/faces and creasing the border but that can be a bit time consuming:



----

Finally, here is the pre-turbosmoothed model, I used smoothing groups to define the smoothing:



Things "fit" more or less and aren't clipping through one another or getting randomly smoothed in places where I dont want smoothing. It only took a matter of minutes to setup the smoothing groups so I found this to be the most efficient way for me.

After sculpting details such as bolts and panel seams, using the normal maps generated from Zbrush work perfectly on the lowpoly, aside from the uv distortions caused by the Turbosmoothing.

Maybe I'm doing something terribly wrong in my other methods though?

My topology could probably be fixed in many ways as well.



Thanks.

Last edited by l3ftnut : 04 April 2013 at 06:06 PM.
 
Old 04 April 2013   #11
(With all respect) This mesh is not modeled "to be smoothed" imho
Don't get it why you want to smooth it with turbosmooth modifier ? Can't you just use the smoothing groups on that chopper ?
 
Old 04 April 2013   #12
Thanks for the comment, you may very well be right. The most important thing to me was to keep it rather low poly for ingame use. I'm well aware that it is far from perfect but I'd appreciate some tips on how I could make it more "smoothing friendly". I should probably try to reduce some of the poles and triangles for better results.

However that is only a secondary issue, I think, since everything I need works almost perfectly.

After throwing up some bolts on the hull, I can extract a normal map which fits perfectly onto my low poly except the places where Turbosmooth has distorted the edge, the bolts seem stretched on those places.

I am using smoothing groups on the chopper inside 3dsm but they alone don't do much when I take the model over to Zbrush since Zbrush does not read them at all. It completely ignores the smoothing groups I had set up.

The reason for why I'm using Turbosmooth is I want Zbrush to distort the model as little as possible when I subdivide it there. If I'd just subdivide it without the Turbosmooth, I'd get similar results to the ones I pasted above.

For me, it is quicker to set up the smoothing groups than using "crease" inside Zbrush.

I saw this Turbosmooth method in a tutorial few months ago, I can't find it again now since I don't quite exactly remember which site/forum I saw it on.

I will be testing Turbosmooth pro soon, I hope that solves the distortions at least, ignoring my other mesh related issues.

I apologize if I'm not getting my points across efficiently, English is not my primary language.

Last edited by l3ftnut : 04 April 2013 at 10:10 PM.
 
Old 04 April 2013   #13
Can I say that there is another way to this pipeline that is worth considering

Start with the High Poly in Zbrush - add the detail/colour and as much as you want - getting the look right in ZB.

You don't have to worry about topology/Uv's or pretty much anything apart from making a good looking model.

Then export the ZBrush model into Max, Decimate it first if you need to in Zbrush.
Retop this model in Max to create a Low Poly - this is the only object you need to unwrap which makes life extremely simple.
Then use Xnormal to project to Colour/Normal/Displacement/Curvature etc... of the original ZB High Poly model.

It's a very fluid workflow as you can alter the high poly or low poly and just re-project in Xnormal.
__________________
Renderfarm hire available @ www.hotknife.co.uk
 
Old 04 April 2013   #14
I'm a bit confused about this. You don't need UVs on the high res model if you're planning to bake normal maps to a low poly model, so distortion in UVs when subdividing shouldn't matter.

The high and low res models don't need to match in any specific way, just occupy basically the same space.

I must be missing part of what you're trying to achieve here.
 
Old 04 April 2013   #15
Originally Posted by robinb: I'm a bit confused about this. You don't need UVs on the high res model if you're planning to bake normal maps to a low poly model, so distortion in UVs when subdividing shouldn't matter.

The high and low res models don't need to match in any specific way, just occupy basically the same space.

I must be missing part of what you're trying to achieve here.


I think the problem was that the unnecessary Turbosmooth upon import to ZB was causing the UV smoothing issues.

I have to agree with hotknife here though: The OP's workflow is a bit messed up. It would be better to create the high-res mesh in Max. Send to ZB for detailing and lastly build the low-res game topology/create UVs. And definitely bake the normals in Xnormal as ZB's normal maps aren't the best.
 
Thread Closed share thread



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
CGSociety
Society of Digital Artists
www.cgsociety.org

Powered by vBulletin
Copyright 2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump
Miscellaneous

All times are GMT. The time now is 09:39 AM.


Powered by vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.