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View Full Version : Incredible exploding blendshapes!


en-gram
03-21-2003, 06:50 AM
Hey guys,

Thinking that I was completely finished with setup...ready to animate. I discover that something has gone completely wrong.

Everthing seems to deform fine...ik is working good with the smooth bind I did...until I move any of the blendshape sliders up.
And then the entire object explodes. In the character's default position...everthing is ok. IK works...OR the blendshapes work. But not at the same time...make sense?

I tried to change the deformation order on the object...but the maya says stuff like..."Warning: Expressions is not deforming polySurfaceShape6." So...it won't let me middle mouse click and drag any of the inputs to a different place.

Let me say that I cut the head off to do blendshapes before I re-attached it and did a smooth bind on the character after. (keep this in mind)

Here is the INPUT Operations for my object [top to bottom]:

Skin Cluster
Tweak(tweak9)
Poly Merge Vert
Poly Merge Vert
Poly Merge Vert
Poly Merge Vert
Poly Merge Vert
Poly Merge Vert
Poly Merge Vert
Poly Merge Vert
Poly Merge Vert
Poly Merge Vert
Poly Merge Vert
Poly Unite
Poly Smooth Face
Blendshape(Expressions)
Blendshape(Phenomes)
Tweak(tweak8)
Poly Smooth Face

------------------

What did I do wrong? How can I fix it? Or should I just start over?
:shrug:

Thanks guys
en-gram

GrafOrlok
03-21-2003, 08:40 PM
This happens when the vertex numbers are different on the blend shape mesh and the original mesh. And this is probably because you detached the heads and then reattached them. This can also happen if you convert the blend shape meshed to subdivs. We had this problem a few weeks ago where a guy was put to do blend shapes, detached the heads and converted it to subdivs. We didn't find any other solution than to let him point-snap a clean copy of the base mesh to the blend shape mesh. A lot of extra work... You can probably find a script that can renumber the vertecies.

A comment on your input list. You have some really unnecessary history left. I would have gotten rid of the "poly merge vert"-nodes before skinning. Same goes for Poly unite and you also have two poly smooth nodes in there. If you plan to go back to low poly by keeping these it might be useful. otherwise it's just bringing performance down. Delete history before blend shaping and skinning!

A tip of how to save your weights (if you don't already know) is to duplicate surface. Bind it in the same fashion you did with the original mesh, and then run a script from Highend3d called transfer_weights_v.mel. It'll make your day.

If you have a zillion blendshapes , maybe you should consider altering the original mesh instead. Make a copy of your most normal looking blend shape and then pointsnap the geo back to the original...

Did I over do this? Well, just wanna help you out!:airguitar

en-gram
03-22-2003, 01:14 AM
Thanks Graf,

I figured I either skipped some steps or just didn't do something I should have done. As I am making the switch from Lightwave to Maya...I'm trying to get used to the way Maya thinks.

I probably should not have cut the head off in the first place...as my mesh did not have a lot of geometry to start with. I just didn't want to have a bunch of copies of my chracter all over the place. I thought that just the heads would be easy to work with. I didn't know that it would cause problems later.

It is funny because as long as my character doesn't "talk"...I can animate all day long. So maybe he is not completely useless now. :)

But unfortuntely, I think I will need to go back to the point before I added blendshapes, or skinned him. Good thing I save often. And I will for sure save my weights with that script. thanks.

The only bad thing about working with polys, is that when I'm doing the blendshapes...I want to be able to SEE what that expression will look like on the character. So it seems for each blendshape I have to constantly smooth it to see what it looks like...then undo. Otherwise...everything runs much slower if every blendshape is smoothed. Make sense?

This is why practice is good...always learn from mistakes. :)

Thanks Graf...I appreciate it.
en-gram

GrafOrlok
03-23-2003, 09:01 PM
The only bad thing about working with polys, is that when I'm doing the blendshapes...I want to be able to SEE what that expression will look like on the character. So it seems for each blendshape I have to constantly smooth it to see what it looks like...then undo. Otherwise...everything runs much slower if every blendshape is smoothed. Make sense?

You don't really have to do a new smooth and then undo it, even though that's a working solution. you can also leave your poly smooth node and select it under inputs in the channel box. Then you can just change the "division" attribute from 1 to 0 and it is "low poly" again. keep tweaking and switch back to 1 to check and then when your done, delete history. Or use smooth proxy or the excellent script "Connect polyshape" found on highend3d.

Vlad Gabriel
03-24-2003, 08:06 AM
U can also duplicate the lowpolymesh scale it a little and in Connection editor connect in Reload Left the In Mesh (The Reload Left will be the mesh smoothed after) with World mesh in Reload Right (The Reload Right will be the low mesh - the scaled one)so that way u could control the smoothed mesh with the low poly mesh.U also have to apply a map with max transparency to the low poly mesh and then turn Wireframe on shaded.

Gabriel

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