Blend shapes tear apart

[ballinger]

why is my poly-head tearing apart, when I perform a blend shade on it. I first mirrored it, combined and merged the edges. i found a plug called "Reconstruct Mesh Tool" that fixes exactly that problem,but its just for maya 4.0.

quote from the mel:
When you make blend shape target face, you want to combine two half of face of different pose. But if you divide and combine shape, vertex order of shape is changed, So you cannot use blend shape. This plug-in solve this problem. You can use this tool for polygon mesh and subdivision surface.

do i have to go back to 4.0????

thanx philip

[mantrid]

firstly...read the other post on blendshapes.

secondly....if you mirron an object, it is scaled to -1. So its local coords remember that. You must revers surface direction, freezes transforms, delete history, and then duplicate it to make blendshapes, then run the blendshapes commands.

[ballinger]

ok read the other posts. i dont think i have this doubling effect. my objects stay in place. and all of them are in the root,- and are not bound to anything.
i hope you were not thinking about nurbs, im using polys. so instead of reversing the surface, i reversed the face-normals. froze them, deleted the histroy, made a duplicate, combined them and then merged them together. i tryed the same procedure on a simple spehre, - and the same thing happens. isnt this a normal procedure to make a head? its the first time i want to animate a face, and i like to work with polys/subd. i gess all the nurbs people are not willing to draw to equal face halfs, just because the blendshape thing tears them apart- after combining. but... yes i know, in the end im the one how makes the mistake, not aliasW. i saw you made your way up, just with blendshapes, from a "likes to post" to a "post addict". i hope your not allready dreaming of blendshapes! and i hope alias will once include a troublesoothing guide with their manual,- for comon problems - like it seems.

thanx philip

[nonquad]

It's a matter of workflow.

Mirroring your face is fine, but you need to do that before you make blendshapes - and not do anything to change the topology or point order after you have started making blendshapes. You have to understand that blendshapes aren't intended to be intelligent at all. They are intended to be simple and fast. All they do, is transfer deformations from one point list to another. If the points in those lists aren't in the same order, the output will be a mess. By deleting and adding faces to your target, you are changing its point order, thereby rendering it useless as a blendshape target.

There are ways to salvage a blendshape with bad point order - but it's exponentially more difficult than just making the blendshape right the first time.

Now, if you have a symmetrical face, and you want an easy way to make left/right counterpart blendshapes, there are some good scripts for that. I suggest mirrorShape. I'm sure there are better options, but offhand I'm only familiar with mirrorShape; I've used it personally and I can vouch for the fact that it works.

The way you would use it is you get your symmetrical head ready, make two duplicates, and do the left blendshape on one of them. Then you select the extra dupe + the left blendshape and run mirrorshape. The script will then mirror the relative deformation of the blendshape onto the raw dupe head -- just by moving points on the dupe head around for you; not by deleting or mirroring any actual geometry.

So there are ways to get a mirrored effect and save time, but as you can see the point remains, never change your topology after you've started blendshaping -- unless you want to create major headaches for yourself.

"and i hope alias will once include a troublesoothing guide with their manual,- for comon problems - like it seems."
No kidding! At the rate this one comes up, a troubleshooting guide would be the minimum expectation. Really, it ought to be printed on the box in large, bold, italicized 50-point impact font:
Maya 4.5 -- by Alias|Wavefront
FOR AN EXPLANATION OF WHAT IS GOING WRONG WITH YOUR BLENDSHAPE, SEE BACK OF BOX
teehee

[ballinger]

hey, i cant tell you how usful this was!!!!!!!!!!!!!!! AMAZING THANX!!!, Whats goin on in the manual?Or here are the missing pieces to the manual?!

thanx philip

[joojaa]

caution sortof a rant!
nothing wrong in the manual it explains how things work (they allways do by the way), not how to implement it. Imagine getting a manual for a hammer with all its possible uses. ok the so search got downgraded in the update!

• you can hammer nails with it
  
• you can use it to throw at the police!
  
• you can probably use it to remove nails too.
  
• you can hammer a screw too not practical but you can!
  
• exelent tool for mayheim, wave around
  
• you can block the elevator door.
  
• and the list goes on for about as many points as there are inhabitatnts in new york (and thats only counting things it has ben uesd for!)
  

Well noquad I second you on that but maybe the diclaimer should read like this
We are sorry not to include a troubleshooting in the manual! the reason for this is that we cannot anticipate all the spesific ways in which you do not coprehend what is happening. Anyway go and ask highend folks they are happy to tell you the answer! NOT

But we realy should make the faq updated with pretty pictures and all so that people get it.

anyway the point is that the manual actualy explains all this its just that A) people are either illiterate or cant find the info when needed C) dont bother since they can post it on the forum.

Now i think if the faq was a bit more user friendly we could attack point C and we can always paste the relevan link. But the other symtoms are beyond us.

none of this is personal but it has become evident that 10 questions seem to pop up 3-4 times a week and its boooring! Its not like we dont have a sreach button in the forums! And its making people who actualy know stuff go away!