Q: Editing mesh on a character that already rigged

rybeck

Hello folks,

I'm helping my friend's project for modeling part, and got a question about it.
The charcter mesh is already rigged and skinned, and the part I am about to do is 'Editing mesh (in polygon).'
Although I am not fully understanding pipeline between modeling and rigging (and skinning), I guess the character will lose current skin if I 'edit' (deleting, cutting, applying retopology) the mesh, which means after the editing mesh, skinning work should be done again from scratch.... Is that right? If so, is there any other ways to avoid this happens?

Thanks for your time,


Rybeck

PS: Maya 8.0 is one that we use, FYI.

Mark Dygert

Generally speaking, when you make deep changes like that to the model after it has been rigged you will need to start over from scratch. Sometimes it can be ok to move things around a tiny bit, but when you add, delete, retopo anything it screws with the rigging pretty good. Skinning info is saved by vertex number, when you add/delete geometry it starts to renumber things. There maybe some fancy tricks in Maya I don't know about but I'm pretty sure you're stuck having to re-rig it again.

When I get a character skinned and start animating, if someone comes along and wants to make changes I punch em in the nuts and tell them no, you made your bed time to lay in it. Don't tell me something is finished then go back on that...
Yeah... so its not a hot button issue with me at all, heh.

rybeck

Vig,

Thanks for ultra fast reply

Main focus on this editing would be adjusting character's limbs (arms, hands, legs, and feet) proportionally correct. I was reading through help files, and found there are a couple ways to do: "export skin weight maps" and "copy skin weight" In order to do this, I may set the limit on editing process (without delete or add any components but just rescaling and repositioning), but still not clear if it is possible story.
If there is anyone who have done this type of 'backward' editing, please enlighten me..


Thank you,


Rybeck

Mongrelman

If you are using maya:

Skin>Detach skin
Edit your mesh
Delete history
Skin>bind skin>smooth bind
File>create reference
Select the file of your skinned model
Select the reference model (using the hypergraph heirarchy makes this easier)
Hold shift and select your edited mesh
Skin>edit smooth skin>copy skin weights (using 'closest point on surface' in the options, I think)

Probably need to tweak a bit after that, but it's better than starting all over again.

rybeck

Lupus,

Thank you for tips.
At the moment, I am working other parts of modeling, so I may try it tonight.
Rigging & Skinning is not my specialty so it may take awhile though..

Again, thanks for input...


Rybeck

nazeil

These may not work in Maya 8, I use 8.5

Solution#1
- do all the edits you need
- after you are done "delete non-deformer history"

In 8.5 this is found under edit>delete by type>non-deformer history

Back in 6.0 it was under the skin>edit smooth skin> delete non skin history (or something like that)

This can get kinda buggy if you have a lot of history. Fun fact though is moving edges/verts/faces does not create history. Making cuts, deleting, or changing UVs will.

Solution 2:

1. duplicate your mesh
2. edit
3. rebind new mesh to the skeleton your old mesh is still bound too
4. go to skin>edit smooth skin> copy skin weight tool> option box

Under surface association you'll have a few options. the two that I use regularly are:

"Closest point on surface" works well if the mesh is still fills the same space more or less

"UV space". this works great if you don't have overlapping UVs...not so great with overlapping...in fact very bad results.

Under "Influence Association 1" choose "Name". That will reweight the mesh to the same joint(s) the old mesh was weighted to.

So after you have those options set, choose the original mesh and then your new one, and hit apply.

rybeck

Hi,

Great reply, I really appreciate for it.
I've been busy with other stuffs, and I may try this tonight...


Rybeck

El_Guiri

hi guys,

yeap...what nazeil and Mongrelman said were the best/fastest practices for doing this kind of job. if you do need to tweak any verts when your done, michael comet has a GREAT skin weights tool AND a bunch of other great stuff!

http://www.comet-cartoons.com/melscript.php