View Full Version : quick blend shape question.

02 February 2004, 12:27 PM
For my rigged character i made about 15 blend shapes for her body. So if she lifts her arm, i have a blend shape deforming her shoulder to make it look right. my problem is this.

i have a layer with all her arm blend shapes, i assigned them to her, and set them up with SDK. once that was done i went to my torso blend shapes and assigned them to her. so i have a blend shape called Arms and one called Torso. and then i also have one called face. should i be putting every single one of these blend shapes on the same...blend shape? i mean select every one and then assign them to her? because when i move the slider for her face to smile, it wont smile if i have already moved the arm or soemthing. any help would be great.

Matt Leishman
02 February 2004, 04:45 PM
I have to apologize ahead of time because i'm not directly anwering your question, but . ..

this is the very reason I don't use morph targets for extra deformation on different body parts. I use clusters (or other appropriate deformers), and have the needed transforms of those additional deformers controlledby new control attributes via the connection editor or driven keys.

just my meager insight.

02 February 2004, 07:38 PM
So, you just put clusters on lots of vertices then? is that what you are doing, i like doing blend shapes becasue i get the results i want really fast is all.

Matt Leishman
02 February 2004, 08:29 PM

for example, I'll put a cluster on the verts for one of the elbows and paint the cluster weights such that when the elbow is bent the appropriate deformation occurs on the elbow geometry. and then i'll just have the translation of the cluster be automatically driven by the rotation of the elbow joint.

I'll use a similar workflow for a lot of different areas on my characters/creatures. sometimes i'll use wire deformers in the same context, or even lattices - it all just depends on what type of deformation is needed for that particular instance.

02 February 2004, 08:41 PM
i tried with clusters before, i got ...not right results i forget what hapend but the clusters were not working right. well my friend is onlien, i guess he is goign ot try and help me figure this out thanks for the info sith.

Matt Leishman
02 February 2004, 08:57 PM
good luck with whatever approach you take.

just as a final word, i've never had a problem with using any of the additional deformers on my geometry as long as I've re-ordered them such that they are firing before the skinCluster node (or rigid bind cluster nodes if you are using a rigid bind).

02 February 2004, 11:00 AM

If you have problems with multiple blendShape nodes canceling each other out, you need to set the default deformation order to Parallel, when creating the blendShape nodes. This is found in the blendShape options advanced menu tab.

If you have allready assigned your blends and don't wish to change that, you could use the edit membership tool to make sure that the different blendShape nodes does not contain the same vert's. This if done by selecting the deformed object, finding the blendShape nodes in the hyper graph, selecting them one by one, and using the: deform>edit membership tool. Press click CTRL to deselect verts.

Hope this helps.
:) Nenox

02 February 2004, 05:09 PM
yah thats great, thanks nenox. so i dont wanna go through all the work of doing then set membership tool, soundsl ike to much work to me ha. So i guess ill have to put my blend shapes on my character again right. what do i do if i have face blend shapes also? cause i have some face stuff and about 15 blend shapes for her body, do i make all of them parallel? or do i make the face blend shapes a differnt order? i have no idea how people figure out theses orders to blend shapes.

02 February 2004, 08:48 PM
Hi. Alot of work to use the Edit membership tool? This is 3D for gods sakes! Things are surposed to take forever! :)

Any how. As far as i remember, you only need to make the first blendShape parellel. The rest can be default. Though i don't think that it hurts to make them all paralell. You will still only get one paralell blender. You only have to set the option once.. but you knew that of course. The paralell blender... well, blends information from multiple blendshapes. I don't know the tech details, but it seems quite logical to me.

As for the head, it depends wether it's a part of the same mesh as the body. If not. Just use default. (Unless you want to assign multiple blendShape nodes to the head as well)

One advantage of limiting the vert's that are deformed by your blends is SPEED! If you don't like to use the edit membership tool you can do the following:

Go to vertex component level. Select all the vert's that needs to be included in e.g. the torso blendshape, and go - Create BlendShape (while still in component mode!) Go to object mode and assign your targets using - Edit blendShape>add targets. Remember to specify the correct blendshape node

By the way if you want to see your deformation order, take a look in the bottom half of the channelbox.

Have fun, you lazy b... :beer:


02 February 2004, 07:22 PM
Nenox, should my blendshape be below everything or above it? cause my character is weighted already. and i am not sure were i put the order.

02 February 2004, 09:08 PM
Blends before skinning! You know how to re-arrange deformer order?

:) N

02 February 2004, 10:11 PM
yes just go to inputs and then all and MMB right?

why before skinning? i have my joints weighted so when i move them i SDK my joint to the blend shape or else i wont know how it is going to deform.

02 February 2004, 10:59 AM
1. That sounds about right.

2. Try it and you will see what goes wrong. Deformers move components around (not transforms). So if you have a skin node first and eg move the root of your character 10 feet to the left, what will happen is that all your verts move 10 feet to the left. If you were to select the characters mesh at this point you will notice that is transform is still at the origin, and has not moved. Now if you fire up a blendshape, that's just a copy of the original mesh in the bindpose, all the verts will move back to characters bindpose. Now if you want that it's cool but i guess it's not.. :) In short blendShapes overwrite other deformation as oppose to other types of deformers (Skin, clusters etc.) This is also why you have to use the parallel blender when using multipoe blendShapes on the same verts ....

Notice that if you add blendshapes after skinning with the options set to parallel, Maya automaticaly puts the blendshape nodes before the skin node.


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