Deformed shoulder mesh animation :(

Hello everyone, I would like to know if anyone can help me with this problem. My mesh distorts something horribly at the shoulder everytime I try to animate the character to lift the arm. I have tried weight painting and read up on the wiki and searched for old posts here in the forum, but I cant figure out what is wrong. Im at my wits end and it feels totally useless to texture the file before I know I can actually use it! sigh

Here is a couple of shots of the distorted animation as well as some piccys of the shoulder mesh in edit mode:

http://www.dragonsnail.com/test/distort.mesh1.jpg

http://www.dragonsnail.com/test/distort.mesh2.jpg

http://www.dragonsnail.com/test/distort.mesh3.jpg

http://www.dragonsnail.com/test/distort.mesh4.jpg

If anyone has the slightest clue as to what is making the mesh distort this way, please give me a hint! Any help would be appreciated! :slight_smile:

The DragonSnail

I think you might want to post less cropped images to see whats going on .
If you can pose your model (with the wierd shoulder verts) and TAB into EDIT mode and take a screenshot of that would help . Better yet post the .blend .

Also you have tris (trianguler faces) in your model . That could be the reason why the distortions are happening , but I can’t tell without more info .

you need complete vertex groups and vertex weight painting. see the wiki for both topics. that one vertex is not part of the group and causes the sharp pulldown. it doesnt blend well b/c of unblended weights.

Well, tris are happening at a lot of places in the mesh, but its only the shoulder that distorts this odd way (and it doesnt distort where the tris are), so I hardly believe that is the problem. =/

I figured there are a certain amount of vertices making a fuss, mostly a couple underneath her armpit. They are distorting every which way, without any order whatsoever. Not sure how uncropped you want the piccys, but I guess you cant complain now… :wink:

http://www.dragonsnail.com/test/distort.mesh9.jpg

http://www.dragonsnail.com/test/distort.mesh5.jpg

http://www.dragonsnail.com/test/distort.mesh6.jpg

http://www.dragonsnail.com/test/distort.mesh7.jpg

http://www.dragonsnail.com/test/distort.mesh8.jpg

I cant for my life understand what those vertices are up to, but if all else fails, I will remake the whole arm(s). I just hoped I would be able to figure out what is wrong, in case it happens again. Thanks for trying to help! :slight_smile:

The DragonSnail

Try just deleting the rogue vertices instead of the whole arm. Then add the missing faces, one by one, and assign weights by hand rather than painting them on. Test each face in pose mode to see how it moves and adjust it before adding the next face.

Also, you might try moving the upper arm bone entirely inside the upper arm. It appears to be starting inside the shoulder joint, which might be causing some of the problem.

I have already added all of those verts to a vertex group (actually, I think they are part of both upper arm and chest, or upper arm and upper back), and they all have the weight of 1.000. I have tried reassinging them to all kinds of different vert groups, though with no difference whatsoever.

I will try deleting the verts, like Orinoco suggests, and make sure the upper arm bone starts where it should. Thanks for helping out! :slight_smile:

The DragonSnail

It’s definitely your topology . Your model doesn’t have the proper edge-loops for the shoulders to bend without distorting . Shoulders are a problem area to model properly for animation for most people , but you have put too many tris in your model - they are a notorious source of making the mesh kink in unwanted ways - I think I saw at least four or five around where you should have had an edge-loop - this is making your shoulder verts pop around like that and also the armpits cross into the surface of the mesh . You have to think about how to layout the surface of your mesh for animation . I mean what you are doing is creating a surface which is emulating the topology of the human body - and this surface - like the human body - actually has to allow for the tension on its surface to resolve itself smoothly . Thats why tris are a bad thing in modeling an animatable surface - just thinking terms of simple engineering - a triangle is stronger then a quad - and if you put stress on structure containing both, the quad will “fail” where the tri will not . Tris put unwanted structure to a mesh’s surface and can lead to the kind of problem you are having .
There several good discussions on this Forum about topolgy in the modelling section, or you can go here The Pole - Subdivision Modeling for a detailed practical dicussion about it .

Thanks for the consistent answer, VP! I have now deleted the rogue verts like Orinoco suggested and remodeled the shoulder area (with quads, mind you), and now it distorts the way I would have expected it to in the first place. One problem is that I really have no clue how the edgeloops should go around the shoulder and so far I havent found any good examples on the net. If anyone has a good example of edgeloops around the shoulder area, for animation, please share! I love to model my own meshes and try out for animation, but god knows its hard to find the “perfect” solution when you have no clue about modeling, really! :smiley:

The DragonSnail

Well, spent a whole day remodeling the upper cchest/shoulder area, and now, finally, the animation distortion is no more than I can live with. Its not like she will run around with her arms held high all the time anyway, so for the small pieces of animation with arms held high its totally acceptable. The only problem now is that its no longer as low poly as I wanted to achieve, but I might still tinker with it a bit and see if I cant lower the poly count. Thanks everyone who helped me get this far, much appreciated!! :slight_smile:

http://www.dragonsnail.com/test/distort.mesh10.jpg

http://www.dragonsnail.com/test/distort.mesh11.jpg

http://www.dragonsnail.com/test/distort.mesh12.jpg

Now I will go on to texturing and making armor, fun fun! :smiley:

The DragonSnail