How can i blend shape seleted area over a mesh?

[arthurf2]

Hi,
I'd like to know if there is a way to make a blend shape only over the area that I want. Let me explain better: instead of make blend shape with my character, I'd like to select only the face to Blend. Because I beleave at this way it will be better to process, once the computer will have to calculate only that area.

ThanX a lot and my best regards for everybody

[nonquad]

Well, to the best of my knowledge a blendshape doesn't retain data for unmodified points... so doing a blendshape on "just the face" shouldn't really effectively be any different than doing a blendshape on the whole body but only modifying the face.

However, what you're talking about is possible, and in some ways desirable even in abscense of computational benefits.
If you want to do it, what you need is a few Wrap deformers. You have to be careful with the settings you use on them, because wraps CAN be slow and unweildy, but used the way we're going to use them, they are fast and reliable.

Here's what to do:

1) Copy your mesh, and lop off just the part you want to make blendshapes for; ie just the face. I suggest giving yourself a few extra rings to play with, just in case.

2) Make sure to delete history on your face-chunk. This will be your new blendshape base. Make copies of it, and edit those to be blendshape targets, as usual.

3) Set up a blendshape, with the "master face" blending to the face targets.

4) WRAP the real, unsliced full body mesh to the blended face. If the model is already bound, edit your history so that the wrap is the first deformation applied.

5) Set the wrap deformer to "points" mode, not polygons, and set a very very very low range. This will set up a situation where each point on the target mesh is correlated to one and only one point on the driving mesh; in other words, it basically just acts like a blendshape (and has blendshape-like speed), but indexed by base point proximity rather than point order.

The full body mesh should now inherit the deformations of the blended "master face".

What I like about this setup, is that it allows you to do a lot of blendshapes on the target region, and look at all the targets at the same time without your machine choking up. It also allows you to do blendshapes in an isolated environment separate from the rest of the pipeline... which may or may not be helpful, depending on the reliability of the group you're working with.

I've also been told that the same effect can be achieved by doing blendshapes set-to-set rather than mesh-to-mesh; thereby allowing you to dictate your own point order. I have tried that technique myself and had zero luck with it... but you're welcome to give it a shot =)

By the way... typing in all caps isn't necessary.

[joojaa]

you can do a set and blend that then iif you are realy carefull with point order you can even make a matching set of only a part of the modell...

But as said once youve done the blend it doesent matter unless you retain history. So the normal workflow would be to make a file where ytou have all the blendshapes and then save it. Collapsse the histry with blend and move on!

[nonquad]

I wonder why it never worked for me that way... I mean I really tried it out...

But when I did the blendshape, it seemed to ignore the order I had used creating the sets, which defeated the whole purpose.

I'll have to revisit it some time and try again. In the meantime wraps do the job.

[gnimmel]

Another way to do this would be to use the relationship editor.

Create your blendshape and open the relationship editor. Switch it to Deformer set editing and you will see your blendshape node on the left. Select it and on the right you will see the blendshape set selected, along with a few others. Using the editor you can add and remove vertex/CV's from the blendshap by simply selecting them (in the main work area as well as the deformer window) and clicking on the + or - icon.
This can be done with all deformer sets so you can add and remove things from skin clusters, lattices etc.

Richard

[joojaa]

Yes that would do but because of how it works totaly unnecesery and redundant.

I think the point is that what they would like is to have a final mesh and then make the blendshapes oly for the head without needing to copy the entire [censored] jsut for that. And indeed it can be done but its not easy as 1 2 3

[campbell]

i havent any success wiring sets into the blendShape either. how do you manage to do it joojaa?

[joojaa]

yes fine if the point structure is the same... Otherwise you will need to go trough the apia nd make a node that masks the points to corresponding ones

[hansesurfer]

supposed the vertex indices are identical, select the vertices from the targets polygon, then select your object face vertices, then do the blend.

unfortunately maya does not provide a way to renumber the vertices...

[gnimmel]

unfortunately maya does not provide a way to renumber the vertices...

There is a trick if you only want to do this to somthing like the head. Simply cut it off and then combine and weild it all back up again. When you combine, make sure you select the head first and then the vertex numbers will be renumbered so that the first X vertex's will be all in the head.

Richard

[campbell]

if the points are the same, for what ever reason (the way the model was built, the combine trick, the reconstruct mesh plug), then there is no point in using sets, obviously.

im still at a loose ends to how you actually blend the sets? (selecting sets to apply the blend to just defers to the shape nodes, per usual, and i cant see how to use the command to do this, nor how to wire it in). could you be more explicit on simply how to use sets?

[joojaa]

No but its possible to make a custom trough set that outputs custom names.

Anyway its also possible to connect the points to dummy atributes that are ordened in the right order and blend that!

But basicaly this is a trivial exercise as the benefits are minimal just doa file and make the blends there then move on. You ccan always recrt back to the file and rebind in minutes if you need. Asuming offcourse your rigging process is automated like it should.

Something is used to do tough id determine the correspondance and let a perl script do it directly into a ma file.... also its possible to make a node that turcates the names accordingly for history retaining blends. I know i have one, but its pain to work on so im looking for expanding it a bit... But havent seen the need for a long time.

sets an make the operation slightly faster... Other than that its no use to actualy try to optimize the blend shape since it does this allready. Altough doing a custom blender isnt that hard.

[campbell]

just to make this absolutely clear:

--> your not actually making the _blendShape node_ do anything particularly out of the ordinary here, it is still just blending between the data on matched indices of shape nodes. there is nothing especially different in the blendShape setup, just that the data on the target shape pnts might not look coherent?

--> sets dont come into the blendShape setup (apart from the deformer's), your just using them for related tasks, and they are outside the actual blendShape network?

[joojaa]

In reply to:
--> your not actually making the _blendShape node_ do anything particularly out of the ordinary here, it is still just blending between the data on matched indices of shape nodes. there is nothing especially different in the blendShape setup, just that the data on the target shape pnts might not look coherent?

Offcourse not. it would be stupid to say i did. Anyway if i could do something like that then we would live in a world thats wierd indeed.

The usual points apply here. Most of you guys are too concerned on how things are designed to work as oposded on how they do! IN general any node based architecture maya included is not at all concerned on what its fed and what it feeds to. Ita alla matter of feeding maya the data it wantsa and then taking out the output.

Its not particulary hard to do a node that east the indexed value and feeds out the values in proper order. It is offcourse infinitely simpler if you stick with the normal workflow. Since it takes time to extract the data in the right order, and even then its only of any use if you retain history without collapsing it. And anyone realy hardly ever should.

All the api node need sto do is eat the shape ino a array and feed it out again in the wrong order. Remeber that blend spaes are not particulary concerned of other than poin data and its relative movement (in any defined space that is)

Sets do limit the setup but maya plunk them out of the way when creating the stuff. Also sets do make the job considerably easier to manage. This and much more stuff.

[campbell]

by 'out of the ordinary', i mean novel (not supernatural, and i dont attribute you those powers).

just wanted to be absolutely sure you wernt wiring blendShape nodes in some obscure way that would instruct reorganisation of the data (yes, you'd still be required to determine the correspondence, otherwise, you'd be absolutely right - the world would be a groovy place, you could just sit back and watch your ideas bloom on the screen). didnt appear possible to me (where does the reorder info go? for one), but ark you never know, and you do pull out surprises! anyway, just wanted to make sure you were still in the same position of having to reorder the data pre or post the blendShape, and not able to do it on the node.