Maya Blendshape questions from a noob

Krisonrik

I have a water tight model, a whole character in 1 mesh. (a nude figure)
I'm trying to rig it and do some simple posing and animation with it. My questions is, can I add blend shapes for muscle deformation and so on with a model that's rigged with bones. Will blend shapes interfere with the bone rig? What made me ask this questions was that my only limited knowledge in animation and rigging was from Max, and while in Max, blend shape seems to lock down the model and bones no longer have effect on the model. Is this true for Maya too? Also, is it possible to just create blend shape for specific part of the body without the need to duplicated the whole mesh? If anyone can point me to a good tutorial on how to do this, I would be very grateful. Thanks in advance.

BuCC

This isn't my strongest subject, but AFAIK combining blend shapes with bones work fine. I've never tried doing muscles this way but facial expressions etc. work like a charm, and I can't see why this should be any different.

You don't need to worry about duplicating the whole mesh. Once you have created a blend shape youre happy with, simply delete the duplicate. The blend shape itself should remain working.
Although I think the smart way to go about this would be to import the duplicates as references and simply turn them off when you don't need them.

Hope it helps, I'm not 100% sure about this, so get it confirmed somewhere.

elte

Yes you can add blendshape after you rig, isnt that the usual way? blend shape will go well along together with joint deformation.

is it possible to just create blend shape for specific part of the body without the need to duplicated the whole mesh?
Yes, let me paste from my blog:

Usually we duplicate the entire body mesh to create a blend shape for the head, but what if the object is heavy? Having few duplicated object will kill your scene.

The solution is to separate the head (extract), then duplicate and do some blendshapes, keep the first duplicated as the 'base' rather than the original mesh because we can't use original mesh as the target due to vertex order change. As soon as blend shape is ready, create a blend shape to the 'base' so it stores information. Then apply wrap deformer to the original mesh.

I know the wrap deformer is killing the scene by computing the calculation together with joint deformation. But the trick here is GO TO INPUT AND CHANGE THE ORDER OF THE WRAP BELOW SKIN CLUSTER. Therefore the wrap deformer is no longer calculated after the skinned deformation. This will dramatically improve performance and resulting cleaner construction history.

Another method is by using combine and merge verts, which leave ugly construction history. I prefer to use wrap instead.

Hope it helps.

Krisonrik

You guys rules, I will have to practice this and see
Thanks again.

vargatom

Watch for deformation order - this is true in Max as well.

Understand the concept of blend shapes: each target/shape whatever stores information for every vertex of your model, which is a point in 3D space where it should travel to as you increase the shape's weight to 1.

Skinning also moves the vertices, driven by the transformation of the bones.

If you apply the blendshape deformer after the skinning, then skinning will still be effective, but the blendshape will then move the points back to where their positions are in the blendshape target object. It looks like the same result but it's actually slower

So, the correct deformation order is to have blendshape first, skinning after that. AFAIK it means that it has to be on top but you'd better check the manual.
In Max, add the Morph modifier first, the Skin on top of that; I'm sure about this one

Krisonrik

Thanks Vargatom, that's very important concept for me to learn.

Krisonrik

I read 2 tutorial on this subject, but here is the part I think is confusing. I make the corrective blend shape out of a duplicated bending pose, and then edit the binding pose with soft mod. But I can't make the bending pose into anything that resembles the body part's after pose. (well I don't know the word, but the state where the arm for example after bending) But I remember I saw pictures of other blend shape related topics that has multiple blendshapes in the forms of different degrees of arm bending. Would anybody please clear this mud for me please? Thanks in advance. Being noob sucks.

elte

Dont really understand what you mean, but if after all what you need is to fix the shape after animation is final, you can create cache for every frame of the model, and do fixing eg like armpit by moving verts via soft mod in a frame that's problematic, then those changes can be weighted over few frames before and after. Although technically I've forgotten the tools, I remember if you go to autodesk maya site, and look for 2008 or 8.5 feature they have 1 vid showing this technique.

Or else you can use cluster, select some verts that you wanna fix, then paint the cluster weight to soften the transition..

Mark Dygert

In Max, we do all of our blendshapes (morphs) before we rig/skin. Copy the base head un-rigged head, make a morph, wash rinse repeat. Then we apply a morpher, then skin.

We use morphs for things bones have trouble controlling. We use bones for things like eyelids, eyebrows, jaw opening.

The great thing about driven keys and reaction manager/wire parameters is that you can also blend in wrinkle maps and rig it all up to a control board, so a bunch of things are being driven (bones, morphs, material blends, look at constraints ect) by one little piece of a control board.

vargatom

Yeah, the workflow for using corrective blendshapes on a smooth skin in Maya is kinda backwards... There are two solutions as far as I know.

One is to use the math behind the blendshapes, it can also be automated using scripting.
Basicaly you have to create additional shapes that you subtract from the model you're working with. Maybe I'm too dumb but I can't really go with it, kinda confusing... One of the Alias HyperReal Rigging DVDs has the explanations and maybe some tools as well. Or ask your local TD

The other, IMHO better way is to use Michael Comet's poseDeformer. Maybe it's still available as a free download, google it - I think it's a much smoother, easier and even better solution.

elte

@vargatom Oh heck how can I forget Comet's PSD.. damn.. Hey I heard someone port it to python script, try to find on highend3d or google, but im not sure whether it's buggy or not.

Mark Dygert

Does anyone know what is the Maya equivalent of Max's Angle reformer (in the skin modifier) or the skin morph modifier? Are those corrective blendshapes?

vargatom

Maya doesn't really have this approach...

Think about it as Max having a nice set of toys, and Maya offering you a bunch of Lego blocks that you can combine as you'd like. There are various kinds of deformers, all with driveable attributes, and you even get an additional layer of control when you get into hypershade and start to explore attributes like inmesh/outmesh or intermediate objects. Then you can move in and add scripting, create your own plugins for deformers and so on...
PoseDeformer is a great example, and it's even more advanced then simple rotation driven morphing, because it works with pose space instead.

So in short there's no out of the box equivalent but you can build your own and most Maya sutdios do so.

Krisonrik

Thanks everyone for providing so much useful info. Now I just have to dig deeper and get my hands dirty with rigging in maya... OUCH...

Mark Dygert

vargatom wrote: »

Maya doesn't really have this approach...

Think about it as Max having a nice set of toys, and Maya offering you a bunch of Lego blocks that you can combine as you'd like. There are various kinds of deformers, all with driveable attributes, and you even get an additional layer of control when you get into hypershade and start to explore attributes like inmesh/outmesh or intermediate objects. Then you can move in and add scripting, create your own plugins for deformers and so on...
PoseDeformer is a great example, and it's even more advanced then simple rotation driven morphing, because it works with pose space instead.

So in short there's no out of the box equivalent but you can build your own and most Maya sutdios do so.

Ahh I see.

[smarmy max know-it-all voice]
Well, max does have the manual method to rig up and script things together using wire parameters and or reaction manager, expressions and maxscript. Its just nice to have some of it built into the tools so you're not stuck rigging it all up every time from scratch.

It's like having a race car delivered with enough parts to build your own but not really needing to go that far.
[/smarmy max know-it-all voice]
It's great that people have scripted some tools to help with that thanks a bunch!