View Full Version : right order for deformers?

 manditri07-01-2006, 05:46 AMHi, i am a rigging newbie.....i was wondering what is the right order for applying deformers. Ofcourse we can change the order later on.....my Qs below- Q.1) Currently i decided on this approach- a) Create the model b) Place joints, Skin and weight(i went half bald trying to nail this) d) Add any SDK/expressions to the joints if needed(for joiints controlling joints) e) Export and store the weight map as a TIFF file for later use f) Create Blendshape models from the skinned geometry.(Not applying the blendshapes yet) g) Detach the skin and delete all its history, Now apply all the Blendshapes through a Parallel Blender. h) Bind the base geometry(with the blendshapes already applied to it) back to the joints. Import the weight map. i) Add clusters or other deformers on the geometry for localized animation control. j) Create and connect control objects appropriately. Is this approach ok ?... Or am I doing some unnecessary steps(I sincerely feel so for steps e to h...i cud just keep adding blendshapes....on the skinned geometry...but i also found that sometimes the blendshapes endup being quirky that way...). Is there need to reorder, add or remove any steps in this approach? Q.2 After the character setup is complete it can end up having quite a few controllers. How do animators keep tab of these. Are the controller attributes grouped into seperate character sets..or are they keyed one by one....or is there some other way...? Sorry about such a long read. Wud really appreciate your help. Thanx
isoparmB
07-03-2006, 05:27 AM
These are my basic steps for rigging a character. This isn't the only way, of course, but I find this flow to be quite efficient:

A) Clean the model, delete all unnecessary history (Return model to unsmoothed state before deleting history, you want to work in the lowest model resolution possible). Do this also for blendshape targets, but remember to NOT freeze transform base and target models.
B) Apply blendshape targets on model.
C) Place guide locators on the model using a script (Really speeds up the layout process, especially in placing finger joints). Layout joints by point snapping joints to locators. Also, layout only one side of the rig (right side for example.).
D) Check rotation axis of joints. Also rename joints to your chosen naming convention.
E) Mirror symmetrical portion of your Rig joints (i.e., right arm and right leg). Check for full symmetry (important for mirroring weights later on), and for zeroed out joint rotations and proper joint orientations. Make sure mirror joint settings are set to rename the other side of your joint setup.
F) Apply IK and controllers.
G) Test rig motion.
H) If and only if rig is tested, skin.
I) Do skin weighting for left side. When done, mirror weights to the right side.

dunkelzahn
07-03-2006, 10:35 AM
Although in my opinion both approaches are correct, I like Isoparms way, because his process is very streamlined, while manditri does the extra step of storing the weight maps seperately and using a lot of tricks for blendshapes and clusters. While this might be a bit more timeconsuming, who knows when Murphy will strike again.

My approach is similar to Isoparm´s, however I have missed out on the automated Mel layouting, good thinking there. I´ll have to try that myself.

Cheers

Chris

manditri
07-03-2006, 01:41 PM
hi,
i pretty much follow what isoparm does...except the automated scripts and stuff bcuz i am not into those yet:)

I wanted to know abt deformation order actually....more specifically blendshapes.

I am working on a charachter where I need to add corrective shapes for the mouth when the jaw opens. This is wat I have done, Jeff Unay in his modelling masterclass does it the same way -

1) Skin the head and open the jaw using joint rotation.
2) Duplicate 2 copies of the base mesh with the jaw open
3) On one of the copies i model the corrective shape
4) Add both the copies as blendshapes(Parallel Blend mode) to the base mesh(Jaw is still rotated open)
5) For the corrective shape the blend slider is set to 1 and the one without any tweaks is set it to -1
6) Close the jaw and duplicate the resulting shape as the final corrective shape for jaw open.

I am confused after this....Plz take a look at the pic below.

http://manditri.com/blendshapes.jpg

On the left is the corrective shape applied as Front of Chain....on the right the same shape is added in Parallel blend mode...the jaw has been rotated open.
Notice the difference in lower lip shapes(marked with dotted lines). I actually want to use the Parallel blended shape as my final corrective shape.

Now if i rotate the head to one side the Front of Chain Shape keeps looking good but the Parallel Blend one has decided to throw tantrums. Maya docs say that Front of chain prevents Double transforms if the mesh is already skinned.

And if i detach the skin, add the corrective shape through a Parallel blender and then reattach the skin the same way it was earlier(i saved the weight map), I get the same effect as adding the belndshape with Front of chain after the mesh was skinned...but thats not the shape I am happy with.

So what do i do....How do i create the correct shapes. Can u guys share ur approaches plz..Where am I goin wrong here.

isoparmB
07-04-2006, 12:14 PM
My approach is similar to Isoparm´s, however I have missed out on the automated Mel layouting, good thinking there. I´ll have to try that myself.

\\start of code

float $pos[] = manipMoveContext -q -p Move; spaceLocator -p$pos[0] $pos[1]$pos[2];

CenterPivot;

\\end of code

The layout script is really very simple. You select the components on your model where you want to place a guide locator, then click the script from a shelf. It will create a locator at the center of the selection. You can then use this as a guide to snap your joints to while you're building joints. It's most handy when setting up finger joints, but you can use it for arms and legs as well, or for any other application. It's not fully automated, just speeds up the rigging process. :]

isoparmB
07-05-2006, 04:38 AM
I would dupllicate your head in the bind pose, apply it as a blendshape to the original, activate the blend weight for your corrective shape (even without any difference now), open the mouth, and then tweak the corrective shape while eyeballing the deformation it makes on the base shape. This way you get exactly the correct shape you want while using the correct setting you need for the deformation order to work.

manditri
07-05-2006, 09:27 AM
I would dupllicate your head in the bind pose, apply it as a blendshape to the original, activate the blend weight for your corrective shape (even without any difference now), open the mouth, and then tweak the corrective shape while eyeballing the deformation it makes on the base shape. This way you get exactly the correct shape you want while using the correct setting you need for the deformation order to work.

Thanx Isoparm. i tried that approach too...I wanted to know whether i shud add the corrective shapes as front of chain or parallel. If i add as front of chain then the subsequent blendshapes(grouped as phonemes, muscle shapes, expressions...etc) wont work together with the corrective shapes. Do i model the phonemes, expressions etc on the unskinned geometry, add them first as belndshapes and then skin the mesh to create the corrective shapes.....or am I confusing myself too much...help me a little more plz :)

isoparmB
07-05-2006, 10:44 AM
Yes, generally you model the blendshape targets first (duplicate the targets from the original before skinning) to avoid complications. This avoids any deformations getting added to your geometry due to skin deformations, which can cause popping geometry apparent when target weights are turned on. This goes for corrective shapes as well. And I did some testing, and yes you can use the Parallel setting for your corrective shape. You apply the facial blendshape first with the default setting, then the corrective blendshape with the parallel setting. Then you can skin.

But in case you apply blendshapes after skinning it's easy to just reorder deformers in the show all inputs section.

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