Maya Blend Shapes Deforming Incorrectly
I have encountered yet another particularly frustrating issue in Maya.
I'm creating my first facial rig for class, and have gotten to the point where I am creating blend shapes. We're supposed to create blend shapes for the eyes, brows, tongue, and mouth, each in separate groups. We were instructed to use the "Default" or "Parallel" method.
I duplicated all of the blend shapes from the original geo and lined them up. Nothing has been shifted/changed/etc. from the original aside from the motion I want (blinking, widening eyes, etc.) I created the first set, "Eyes", with no problems.
The next day, however, I realized that whenever I created a new set, regardless of whether it's "parallel", "front of chain", "default," etc, the base model's skull stretches upward, even though both the base and blend shape model are EXACTLY THE SAME.
I've tried:
*re-duplicating the original geo and creating test blend shapes (same result)
*deleting the "eyes" group, altering the blend shape type, then creating the new group ("eyes" group also stretches when I do this)
*re-ordering the inputs (either they won't move or moving skin cluster above everything else deletes all deformer history and shifts the base model in an unwanted fashion.)
Keep in mind I did NOT freeze transformations on the duplicated blend shapes. That seems to be a common cause, however that is not the case here.
Also, the only blend shape type that doesn't shift is "Default", however using that overrides my other blend shape sets, which isn't what I want.
I am at my wit's end with this model and can't wait to be done with it. :poly127:
Can someone please help me? I've spent all weekend on this and need to turn it in ASAP.
Thanks in advance.
I'm creating my first facial rig for class, and have gotten to the point where I am creating blend shapes. We're supposed to create blend shapes for the eyes, brows, tongue, and mouth, each in separate groups. We were instructed to use the "Default" or "Parallel" method.
I duplicated all of the blend shapes from the original geo and lined them up. Nothing has been shifted/changed/etc. from the original aside from the motion I want (blinking, widening eyes, etc.) I created the first set, "Eyes", with no problems.
The next day, however, I realized that whenever I created a new set, regardless of whether it's "parallel", "front of chain", "default," etc, the base model's skull stretches upward, even though both the base and blend shape model are EXACTLY THE SAME.
I've tried:
*re-duplicating the original geo and creating test blend shapes (same result)
*deleting the "eyes" group, altering the blend shape type, then creating the new group ("eyes" group also stretches when I do this)
*re-ordering the inputs (either they won't move or moving skin cluster above everything else deletes all deformer history and shifts the base model in an unwanted fashion.)
Keep in mind I did NOT freeze transformations on the duplicated blend shapes. That seems to be a common cause, however that is not the case here.
Also, the only blend shape type that doesn't shift is "Default", however using that overrides my other blend shape sets, which isn't what I want.
I am at my wit's end with this model and can't wait to be done with it. :poly127:
Can someone please help me? I've spent all weekend on this and need to turn it in ASAP.
Thanks in advance.
Replies
Here's some screencaps to illustrate my problem.
Here is my base mesh (bind pose?) alongside a duplicate of "r_up" to demonstrate what the blend shape actually looks like. The "Brows" group was created with a parallel node.
This is what's going on when I slide the blend shape's influence up. Sliding multiple sliders creates an additive effect on top of this.
The initial group I made, "eyes", does not do this however.
I searched the internet and found that the deformation order may be to blame. However when I try to move something in the stack, I either get this error, or all of the nodes are deleted except for the skincluster.
Any idea what it could be?
You want to make one blendshape with all your blendshape heads and make a separate control GUI based on the technique described in the book Stop Staring 3. Right now you're looking at a systemic error. In other words the overall system your teacher is having you build is flawed and not any easier/quicker than the correct osipa style system. Its a waste of time to continue with your teachers system. A lot of teachers teach useless, bad techniques and this is one of them.
I'll post again if any new problems arise. Thank you so much for helping!
The blendshapes are overwriting the transformations on the model. For example, if I turn the head first, then slide the blendshape on, the head reverts to the default position. When I slide the blendshape on and THEN, turn the head, the head refuses to turn, and only the teeth and eyes turn with the controller. Trying to change to deformation order results in the same error I posted before.
EDIT: Putting the blendshape underneath the skincluster in the stack DOES work, however the face does the weird stretching thing I mentioned before, in addition to the blendshape.
you probably froze transforms or deleted history at some point and now they are in different coordinate systems. I would go back in saves (you saved incrementally with an unlimited save amount, right?) until you find the error
Make sure your are completely done with your main mesh before you split it off to make the blendshapes. Delete history and freeze transforms first. No more topology changes (obviously), no UV changes etc etc.
Duplicate your mesh, isolate and do your changes. Rinse and Repeat.
Also, in maya, you can have your blendshapes after skin deformation.
BUT - If you are going to export your animations to a game engine, all current commercial engines require you to have your blendshape before the skin deformer.
SO unless you have a this feature supported in your engine, then i would make sure its working set up correctly.
not really adding any new info here...but who knows..
Thankfully there are no game engines involved here! Did everything in the order you mentioned.
I honestly don't understand how I am prone to all these weird bugs/roadblocks.
They shouldn't? O_o
While poking around I discovered the "Paint Blend Shape Weights Tool" and noticed that every blend shape's weight maps flooded the entire mesh with white, so I thought it might be a good idea to change that. It stopped the weird vertical stretching, but now the lower lip is slipping when I rotate the head...
Are you saying that I shouldn't have messed with those and it might be something else?
EDIT: Finished painting the blend shape weights. Looked great until I turned the head. Eyebrows piercing through forehead. Not good.
Whew, thought I screwed up there for a second! Yes, they are on the base mesh and not on the targets.
I have some screencaps of what's going on now. Changing the deformation order yields two very different results. One is more "right" than the other, yet they still both look very bad.
First one is head rotates + jaw opened + mouth expression + eyelid up.
Second one is head rotated + eyebrow up.