PDA

View Full Version : Weight Map Distortion


yosemite
10-08-2004, 12:39 PM
Hi guys,

Is there anybody out there who can tell me what's going on?

I have a character modeled with NURBS and a skeleton saved to another layer. When in Layout, I try to rotate his hand/wrist but something 'awkward' happens.

Not only does the wrist rotate accordingly, a lot of the mesh distorts not necessarily next to the bone of the wrist.

I've checked, merging points and polygons; that all polys. are facing the same way, that the weight maps I have are where they should be etc.

What's going on? I hope I explained that clearly. Please! Please do reply if you even 'think' you know.

Yoyo

Integrity
10-08-2004, 03:44 PM
Go to the object's Object Properties and set the subdivision order to last. That should clear up the problem.

I hope this helps.

yosemite
10-08-2004, 11:57 PM
Integrity, mate - thanks loads but that didn't resolve the problem. It seemed to just alter the distortion into another peculiar shape. Arrgghh!! Got any other ideas?

Yoyo

LFGabel
10-09-2004, 12:20 AM
Sounds like you have some errant points that share the same weightmap. Make sure all the verticies of everything except the area you want to affect are cleared or set to zero.

yosemite
10-09-2004, 12:57 AM
Hi LFGabel, I just tried that and the problem (shock horror) still persists!!! A clever idea I never thought of though.

Ugghh! This is going to haunt me for the rest of the year - dang nammit! I can't believe I've come this far only to be .... made insane! (I'm too unimaginative to be insane) If anyone's got any more techniques, tricks, ideas I'll dedicate an entire rosary to you!!! Please please please!

Yoyo

SplineGod
10-09-2004, 04:33 AM
I would set the bone falloff to ^128 and not use weight maps and see what happens with just using the normal bone influence. You dont have to use weight maps. Bones work as soon as you rest them. After testing deformations without using weight maps then you can determine if and where theyre needed. Also, you dont mean NURBS but SubDivision Surfaces since LW doesnt support NURBS. :)

LFGabel
10-09-2004, 06:49 AM
Can you post an image of the problem?

yosemite
10-09-2004, 11:30 AM
Spline God - Hi, I thought that by using Weight Maps I would be more likely to control the area affected - at least that was my understanding. As a side note I thought Newtek/Lightwave referred to their SubD as NURBS - I was trying to be consistent with what I thought was the vernacular - my apologies.

Okay, that said, you're idea didn't seem to work. But it was a good idea - one which I won't forget as with the other guys. This is really doing my nut in now. There is just no reason why this is happening! (...and last night, those suicidal dreams returned - oops!)

GFLabel, image? Sure thing!

Thanks guys.

Yoyo

http://www.geocities.com/a9625192/deformation.gif

LFGabel
10-09-2004, 04:45 PM
After seeing it, I am certain that those are errant vertices that have weight values applied to them. The curve of the errant vertices matches the rotation of the wrist. The weight maps in question should be easy to find. Just go into weight map viewing mode, and go through all the bones in the hand, even the fingers. You can do this in modeler or layout.

You can also save-transformed a version to bring into modeler for further examination.

But I agree with SplineGod. Use weights only when you absolutely have to.

SplineGod
10-09-2004, 08:49 PM
Spline God - Hi, I thought that by using Weight Maps I would be more likely to control the area affected - at least that was my understanding. As a side note I thought Newtek/Lightwave referred to their SubD as NURBS - I was trying to be consistent with what I thought was the vernacular - my apologies.

Thanks guys.

Yoyo

The "NURBS" thing came from the term "metanurbs" which was a marketing term for SubDivision Surfaces. :)
Just for fun, remove the weight map assignments from your bones and set the bone falloff to ^128. See what that does. Weight maps are more likely to NOT give you proper control right off the bat. Using them up front only complicates a simple task. Its better IMO to weight until AFTER youve added bones, rested them and tested deformation to see where you MIGHT need to use them. Worse case is that it will still take the same amount of time to apply them, best case you might not need them at all.
Waiting until the end is far more likely to save you time and headache. Lightwave bones work just fine without weight maps. If you model with the idea that youll be using bones it really simplifies it. Its a lot easier to spread the fingers on a hand for example when you model it to eliminate possible bone cross influence then to stick weight maps on the fingers and try to tune them. :)

yosemite
10-09-2004, 09:21 PM
Lee, firstly - sorry for misspelling your name in the last post, I only just realized.

...and secondly... this is hard for me to write because the last thing I want to do is to try and convert anybody from a belief/conviction they have. I 'know' you guys think it's the vertices being connected to the hands weight map - but please understand that I have: gone through each annoying vertice in question and checked what weight maps they are active on, and it's none.

With you guys suspicion on the weight maps - I deactivated the map for the bone in the hand. The distortion never altered.

I really don't have a clue what to do now. I'm well miffed. I've been looking all over the place for the past two days and can't find an answer. (...or certain reason for that matter)

The only thing I came across which might have potential is to mirror the right sides weight map but I don't know how to do that. (Is it even possible?) That of course goes along with the idea of continuing to use W.maps.

I must seem so dense to you guys - I'm so sorry, I feel like I shouldn't even be bothering yous any more.

Yoyo

SplineGod
10-09-2004, 09:40 PM
The problem may be one of several things:
The bones arent properly rested, you dont have weight maps on every point or every bone isnt assigned to a weight map. In Lightwave all bones effect all vertices. How much influence one bone has vs another is determined by the falloff and the distance each bone is from a vertex.
If a bone is unassigned to a weight map it can influence any point, anywhere. Go thru all your bones and make sure they are assigned to not just a weight map but the proper weight map.
As was mentioned earlier, one you start assigning weight maps EVERY point must have a weight map of some kind assigned to them. If none of this works Heres what I would do:

1. Turn off the weight maps. Go to your rest pose, select all the bones and hit the r key to make sure theyre properly rested. You also need to make sure you have a proper rest pose (ie the bones match the geometry when nothing is active).
2. Set your falloff to ^128. Test the area that is having the distortion problem to see if it still has problems without the weight maps.
3. Test the rest of the deformations to determine where you might need a weight map vs using a hold bone or two.

yosemite
10-09-2004, 09:55 PM
Roger-roger Spline God, will try it - will try ANYTHING at this point. It's late here of course and another day spent like this is NOT what I need. Will get back ASAP and let you know what happens.

Yoyo

glenporter
03-31-2005, 03:42 PM
I've had this same problem happen to me before! What worked for me was to unassign the weight maps that seemed to have the problem, go back into the bone properties panel and assign the bone the correct weight map (Old school! not using Scene editor or spread sheet to do it!) not sure why it worked but it did! There's always more than one way to do the same thing!

Hope it helps!

CGTalk Moderation
03-31-2005, 03:42 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.