Very urgent problem with painting weights

[daniel-tunjic]

hi everybody!

First of all: Thanx 4 reading this!!
This problem is very urgent! I need the solution VERY fast, because by the end of the week I'll have to be finished with my animation and all the work is still waiting.

The problem:
I've a quite simple looking character to animate. The character has to sing and to walk around. I built the character with polygons and splitted and seperated the head from the body. Per Blend Shape I made the head sing to the music. After that I combined the neutral BlendShape back with the body and merged the border edges. this worked perfect. My character sings.
Now I've setup the joints and all the stuff around and now I want to smooth bind the skin to the joints. Works fine but only the paint weighting does not apply after I painted everything. I click a joint in the toolbox list, paint my weights, and when I quit the tool my paint didn't apply. It doesn't loose the info if I click an other joint from the list during paintig and click back to my previous joint, but when I'm finised with paintig and quit the tool, the whole work is for nothing.
Where is the problem?

Any answer appreciated!
thnx!!!
Daniel [Maya 4 @ Win2K wit no Service Spack]

[gnimmel]

Personaly I've never seen this problem before, but then I try not to alter the mesh after it's been skined. At a guess, your problem is probably due to a history issue with the way you did things.
IF this is the problem, it might be a better idea to combine the head back to the body before you skin it and add the blends. If you cut the head off, and then combine it back to the body, (selecting the head first then the body) the resulting mesh will have it's vertex's reordered so that vertex 0 to number in head are the first vertex's. You can now make a blend shape and turn off check topology. This will result in the ability to have a solid mesh, but only have blend shapes for the head and not the whole body.
IF this fixes your problem, you could posibly save your skining info using the saveWeights script found on this web page. You might also be able to save the head animation you've already done by saving the blends as a clip.
Hope this helps a little.

Richard

[daniel-tunjic]

I really appreciate your answer, Richard!
But somehow I am lost in my own nescience.
Why? I'm a quite newbie in 3D world and this is my first real project and I'm on my own.
I thought that UV Editing is one of the last things in the workflow that has to be done (because uv > texture > shading > last thing before rendering).
the problem NOW that comes in addition is that any uv editing can't be simply deleted from the history because the blend shape would be deleted too and deactivating history tracking doesn't work (it tracks my editing further).
So, all I can do is go back to modelling phase do the uv stuff, copy paste the blendshape animation (make a new blendshape with the same targets but the new neutral head that has the right uvs) and THEN skin the new thing again.
And this time I'll do it like you told me..
Hope it works...
... thank you very much anyway.

Daniel

[gnimmel]

You're right about the history problems with skinning, uvs, etc. but before you start again, there are a few ways arround it. The simplist way is to duplicate your mesh and do all UV editing on the duplicate. When you are happy with the UVs, you can copy them to your real mesh and then delete the duplicate. To transfere them use Polygon->Transfere and set the options to UV's.
A better method is to use the copyWeights script found on this site. It saves weights by either vertex position or vertex number to a file, and unlike the built in method, it actualy works very very well. After you use the script to save the weights, you can delete history, skin it again and use the same script to load back in your skin weights. This script has saved me so much time.
A possible way to fix your problem: I'd set up a character and save the facial animation as a clip. Then I would save the skin weights by position with saveWeights.mel. Next I'd cut off the body, which should keep history and still keep the animation of the face. Using this I would duplicate all the blend shapes again from just the head(there is a script on this site that does this for you). Delete history on the mesh and combine the head and the body again (select head first), and weild up the neck. You should now be able to add back in the blend shape node and turn off check topology to use the new blend shapes. Next skin it again and load back in the skin weights. Lastly set up the head character again and load in the clip to get back the animation. In trax, you can turn back on the keys and delete the clip if you just want the keys back again.
After writing this it may just be easy to start again, but hopfully it will point out a few features of Maya and ways arround things.

Richard

[joaomontenegro]

hey - ive had this same problem before, and i feel a little bad posting because i cant for the life of me remember how i worked through it! However have you tryed editing the weights though the componite editor instead of painting weights? sorry i cant remember how i got though it.....maybe it will come to me in the middle of the night

[daniel-tunjic]

//******* THE FOLLOWING TEXT IS ABSOLUTELY WRONG ***** the reason is at the far end of the text in these quotas again//

once again: thanks very much! this ideas are >very< cool!!
Somehow I'm angry about myself that I didn't discoverd the Polygon->Transfere option earlier or at least saw it in the documentation, where I spend a >LOT< of time
So back to the problem...
You wrote "After writing this it may just be easy to start again, but hopfully it will point out a few features of Maya and ways arround things". Unfortunately you're right! Until now I almost finished the skinning job by starting again, but the scripts you mentioned are really astonishing!
The only script that somehow snails (does this word exist?) is the sds_poly_smooth_weights_export script I found on this site (and I think it is that one you meant, isn't it?). I think I can remember that Maya 4 wasn't on the list of supported versions, but it seems to work anyway. I really have huge time pressure, so I just had to kill maya.exe in the task manager after 20 minutes exporting the weights. But I think my P3 500 is still a main factor in my whole problem universe
I tried to solve it your way, but I couldn't keep going on at the far beginning, because when I combined the neutral head with the body before (!) I created the blend shape deformer, the whole blend shape fails. The head seemed to implode on the first look, but on the second I think I saw the reason: The vertices didn't renumber the way we wanted (neither if I combined the parts with history keeping nor without) because the shape had an overall form of a head, but the polygons showed into any direction within the heads form.
So I just did the following:
I took the neutral head of the existing blendshape set, copied it, made my UV stuff, made the UV stuff of the body, killed the history, made a second blendshape deform set with the same shapes (so I had 2 blend shapes with the same faces but on different targets) and then copied the keyframes from one to the other set. After that I combined the new head to the body, made a "UV layout" command (that produced a good job, but took a long computation time) and started skinning again from the beginning. When I look now on the history of the body there are still the polyUnite, polySewEdge, polyLayout, polySoftEdge a tweak node (I absolutely don't know what tweaks are), the skinCluster and the "Singing" Blendshape nodes.
I know this is not a solution, but it works overall and the performance is not too bad. Thank you for your efford anyway!
Right now I am drawing around on the shoulder and it looks good. By the way...
I hope you won't be angry when I say that I found out why my drawing work wasn't applied; you know - the first problem of all others;-) . It's a fault of a newbie as usual and I found the solution in the documentation: I mainly used the Replace (with value 0) option of the painting to substract the values from a joint. Because Smooth-Binding works by sharing one vertex value to more joints and keeps the sum of those values to 1, it always added the missing values of the sum to the other joints when I replaced a value with 0. So every time I draw an area "black" and thought it was OK, the same area went white on an other joints skinnig info, that shared the same vertex. So I was always killing my work by doing it. In the documentation stands that this process of keeping the value to 1 is called "normalisation" and it can be disabled (in the Edit Smooth Bind Menu), but it doesn't work here in Austria for some reason (surly my fault again)
So my workaround is not to replace by the value 0! I want an area to become black, I have to select the joint that should have this region white and add the value 1 there, so my originally area that should become black, becomes black!
Somehow I always rember those words: "Expirience is a hard teacher. It gives the tests before the lessons."
Let my final words be: Thanks, Read the ******* manual COMPLETELY and "Never give up, Never surrender"

Yours, Daniel

//******* AND NOW COMES THE REALITY ***** //

Dear Richard,

Forget what I wrote there! THIS IS NONSENSE!!!!! If anybody here should have the idea to do a animation in the way I descibed the animation will NOT WORK..
Why?
I am finished with skin painting and wanted to start animating the body, but here comes a problem that I complete do not understand:
Everytime the blendshape animation (facial) and the other animation (legs, arms, tail) come together the whole shape seems to implode.....
oh man... I'm totaly lost now..

[gnimmel]

The reason for the imploding mesh is probably due to vertex order. All blend shapes do is move vertex 1 from point a in mesh a to point b in mesh b of the same vertex number. This means even if your mesh has the same number of vertexs, faces etc, BUT they are in a different order, it will produce very strange results.
This is the reason I sugested cutting off the head and then combining it again. By doing this the head vertexs get re ordered starting from vertex 0 onwards.
The save weights script you mentioned isn't the same one I use. In the mel script/animation section is a script called saveWeights.mel by BigIdea Productions. This one is very good and has worked for me very well. I was actualy using it yesturday yet again to tweek a already skined mesh.
If it makes you feel any better, I think most people learn all these problems the hard way, I know I did. I remember one of my first maya characters was set up about 5 times from scratch due to learning all the issues with set up, UV's etc. It was actualy a good thing in the end because of what I learnt about maya. When you do finaly solve all your problems and get a working character, you'll probably have learnt more about maya than any manual can teach you. It can be frustrating though.

Richard

[daniel-tunjic]

First of all, you'll may have to wait until all included images are downloaded from my server to you... (4 screenshots) It's good to know that I'm not all alone and that the hard way is the usual way. I couldn't sleep because of that problem and took the Maya docu. again and searched for help and I found one:
--
Double transformation effects
A double transformation effect is where skin object points are subjected to the action of a joint more than once, resulting in extreme, undesirable shape changes. Double transformation effects can occur if the skin object points are also being affected by a deformer that is in turn affected by the joint's actions. For example, if after skinning you create a cluster deformer to further
control certain skin object points and then parent the cluster deformer handle to the joint that also affects the skin object points, when you move the joint the points will be affected twice over by the joint's action. One way to remedy this is to organize the affected points into a set that is only affected by the cluster deformer, which remains parented to the joint.
--
and I think that exactly that happens when my blendshape animation and the skelleton changes it's pose.
I read more and found something in the chapter "Editing advanced deformer creation options". There was a "Deformer placement" link decribing the available options of this parameter. And one of this was "Front Of Chain placement". Read this:
--
Front Of Chain placement is available as a creation option for blend shape deformers only. A typical use of blend shape deformers is to create deformation effects on a skinned character. Front Of Chain placement assures that blend shape deformation effects occur before the deformation effects provided by the skinning occur. If the effects were to occur afterwards, undesirable double transformation effects could occur when you pose the skeleton. (For more information on double transformation effects, see Double transformation effects).
--
So I think that this is really my problem! I can do what I want but I have to BlendShape the head AFTER skinning, don't I? I have made some screenshots to visualize everything Here you can see that the skin is following right (although the shoould is quite hard-edged

And when the blend shape comes: Tada! Uncle Cracker, ha? (look at the tail!)
So I exported the weights with the maya export weights option as a luminance map. I think that the best idea when you consider the following problem: The renumbering doesn't work as you said. I tried everything possible way (and surly the way you said), but somehow I'm not able to do the simple blendshape now. So when I export it as an map, the numbers of the vertices are not important - only the uv info, and the uv layout doesn't change, even if I cut and combine.
here is everything without blend
here with. Notice that the neutral head moves to the target, although they have the same origin at the world's origin
So, I already missed the project. Today I should have finished it. But I won't give up. So, to finish it, I would give you the source file to check the problems on your machine yourself - if you want to. I will send you a private message with the url, so that not everybody in the world has the source, ok?