Need help with Rigged Blend Shapes. Please Help!

[drewantarctic]

I figured I'd give a simpler example here. Pretend this is the arm. The highlighted object on the bottom is the target. the two at the top are more obviously the joint affected blend and the resized blend.

So please, if anyone knows anything about this, give me a lesson.
http://www.bushheads.com/bodyBlendHelp2.jpg

[_stev_]

Did you reorder your inputs?

[clalan]

what happens is probably this: in your target shape you make the arm shorter (by moving vertices up in Y direction). when you rotate your skeletons arms up and then blend the target shape to 1, you'll get a totally different result because now moving vertices in the Y direction will not make your arm shorter, as your arm isn't alligned in the Y direction anymore!

a better way to achieve the results you`re looking for:
- add a blend shape with target shapes
- add a skin on top of that

this works fine for target shapes that make characters fatter and all, but not for instance if you want to make your arms shorter. because then you will tear the hands away from their joints and your skinning will give an entirely different result. changes along the axis of the joints can be made by stretching joints rather then blendshapes.

so use a combination of blendshapes (under your skin) and stretching bones to create variance.

[drewantarctic]

What both of you say may work. i havent tried any of that given that rigging and such isnt my specialty. Could you please expand a bit on what you say? I am a little comfused by how brief your answers were though i almost understand them. A few directions would be very helpful to me.

[_stev_]

After you create your blendshapes in the channel box you will see the blendshape on top and the skin cluster below it. In the 3d view, hold RMB over your object and choose Inputs>All Inputs. MMB drag the blendshape and drop it over the skin cluster. Close that. Now in the channel box the skin cluster should be on the top. That should be it.

Stev

[drewantarctic]

Stev, I had tried this method before and unfortunately it still doesnt work after re-ordering even in the simple scene. I'm not sure if I am doing something specific wrong like maybe my settings are skewed or something of the like. If you don't mind taking a look at this simple 270kb scene I would appreciate it a whole lot. Maybe you can manage more than I have been able to.

Here is the link for anyone who doesn't mind looking at it.
http://www.bushheads.com/TestBadBlends.ma

Thanks for your help so far. I really hope I can nail this very frustrating obstacle. Its the last thing I do before I start animating.

[clalan]

don't use your skinned shape as a blend target. first create a blendshape with the shape changes (e.g. fat belly, thin arms) and then apply a skin. both blendshape and skin should be on your final mesh, and in that specific order (1st blendshape, then skin).

but what you are trying to do here: making the arm thinner + shorter is simply impossible using just a blendshape. use a blendshape for making the arms thinner, and joint stretching for making it shorter.

[_stev_]

Here's an example of what the setup should look like. The "skin" object should be your actual character's skin, and the two shapes next to it are the duplicates.

Make sense?

[drewantarctic]

I was really hoping I could keep the skinned mesh as a target. What I was trying to do was create variations of different lengths and sizes of the same body. So with a series of blend shapes I would be able to key through different body types and basically shape shift while keeping the skeleton relevant. This cant happen i suppose. Theres going to have to be a change of plan in the absense of that working.

Tell me if you guys know of a way to SDkey or change the location of a joint with a slider os some type, rather than the translation (because i dont want to affect the skin just change position of rotations). If that would work, it would be sufficient to keep things simple and not have to make completely seperate bodies.

Once again, thanks for both of your help this far.

[underearth]

man are you using whole mesh or just chop off the arm and then apply blend shape...

make sure vesrtex order is correct..
i think this is not the problemm as problem is of scaling..

but today only in tongue shapes i resized my tongue(characters) and then apply blendshapes.. it worked fine...
makbe skinning is the issue to blame.. but i have seen guys applying blendhsape to skinned mesh..

well let me go throgh some old files ...and post something usefull.

[niralrajani]

just add blend shap for the GEo first with Advanced option "front of chain" and lock the blend shap channel...
Then and another blend shape which is gonna control by joint with same option i.e in advanced tab.."front of chain"..
and it will work.......

[underearth]

hey good niral..

if that works...
but tell why you locked that previous node what that suppose...

thanks
sunny

[drewantarctic]

Niral. I am having problems getting your advice to work for me. Maybe I misunderstand.

-I create a blend shape using one of the deformed shapes in front of chain.
-Then (ive tried both) add a blend shape to the first blend row (which doesnt give me an option to front of chain) or create a new blend shape (which doesnt blend while the other is on.

If you would'nt mind taking a look at the file I have attatched earlier and see if you could get it to work, I would very much appreciate it. [/url][url="http://www.bushheads.com/TestBadBlends.ma%3C/a%3E"]http://www.bushheads.com/TestBadBlends.ma (http://www.bushheads.com/TestBadBlends.ma)

[drewantarctic]

The file above is about a 200 kb file by the way. Don't be afriad of it. It's a dummy file, the same basic tube setup listed above. I just want to see if anyone can get it to work so I can see it for myeself. I am working on a way around this...basically the hard way right now by re rigging every character. It would still be nice to get the simpler method to work. In fact I know there HAS to be a way to do it aside from my relative rigging inexperience.

Underearth, I didn't mean to avoid you. Basically what you see (with reference to the arm) is how I split my body up...its divided into 7 shapes, L and R Jacket (what you see is the R Jacket) L and R Jacket Collar, L and R UnderShirt and the Tie. There is a seam in the back that splits it all up. I aim on never showing the backs of these characters. The Vertex order is cool I think. It's just duplicated from the original with no geometry added. Nothing too fancy, except for this one problem.

[underearth]

hi,

first of all your bush head concept art and his head is great.. :applause:
now for problem part..firstly i would like to say that blend shape works in very diffrent way..
i would like to quote from stop staring book "there is no shapes only diffrence"
blend shapes never work the way we suppose it to be (as a general idea) its what the diffrence between base and target shape that counts....
whatever "clalan" has stated in his reply is correct..(man you got good knowledge way blendshape works).Now what you did in your testbadblend.ma file is that your "c" shape and "a" shape are totally identical.. but "b" is scaled down mesh (or new mesh) smaller than "a" & "c" (it has sum arbitary transform value too which does affect blend shape as everything lies in difference of shapes) when you applied blend shape shape "a" does not affects your mesh at all and "b" affected it 100% because of difference in shapes but when you rotated the joint the difference comes in to play as now shape "a" has some shape difference..and you got result which is coming to you as it is the way maya calculate blendshape so nothing is wrong in scenefile..

so to achieve expected result...

take out model "a" duplicate it and make mesh changes (like wrist or muscle bulge etc.) we call it "b" and the make another duplicate of "a" and now apply both blendshapes to "a" & "b" to new duplicate this become "c" and now scale it down (as you wish to scale it without loosing skining and rigging you have done...

NEVER EVER DO FREEZE TRANSFORM ON TAARGET OR BASE BLENDSHAPES...
i have attached scene file.. hope this is what you want...

if i am wrong somewhere Please point and i am eager to learn what went wrong

thanks

sunny

[drewantarctic]

You guys are just full of bad news! haha. Well, at least I know one thing for sure, and thats one thing more than a did a few weeks ago. Thanks to all of you for really giving it out for me. I really love this community for that one reason.

BTW, if anyone CAN make this work, let me know. For me, its back to the drawing board..

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.