Maya Blendshape system

[snake3y3s]

Maya 2018.2's Blendshape system is scaring us... its doing some sort of mystical sorcery in the background and I would like to get some clarification on it before continuing.

So, by my knowledge/experience (14 years) when creating blendshapes, maya is basically storing the delta changes of a vertex, and its vertex ID, and then blending between its base and the target delta, so, in saying that, if one were to change the vert count...in ANY way, (adding edge, deleting extruding...anything really) in tern changing the vertex counts and IDs, this should break all your blendshapes.

with the new shape editor... this does not seem to be the case anymore... what gives O_O

I have created a head, added targets, made a target shapes and then gone back into my mesh and deleted a mouthbag, made extrusions and cut in a new edge, deleted non-deformer history and all my blends are still fine. I'm scared because although all this is really cool and makes life better... im dreading that it will eventually break somewhere down the line.

Is maya creating the targets off of the base blend shapes as instance meshes in the background?

[Christoph_Schaedl]

im not 100% sure but i assume its doing a bake to target in the background if you change something...

https://www.youtube.com/watch?v=BFPAIU8hwQ4

[snake3y3s]

Thanks cg_oglu

I have watched that video before and I am well versed on the usage of the shape editor.

My question is what exactly is it doing in the background... kinda hoping that a Autodesk/maya developer sees this and responds.

[snake3y3s]

Are there any Autodesk devs that can aswer me as to what the shape editor is doing under the belt?

[mspeer]

Hi!

You description about how Blend Shapes work is generally correct.

It's not recommended to change the vertex count / topology after creating blend shapes.

It may "work" in certain cases but this is just luck. While some already created blend shapes may work fine after changing the original mesh, some further editing of targets can become impossible, because the selected vertex from original mesh and the target mesh will no longer match.