How to rig character with ERC Freezing

[Anonymous]

Hi there, after spending almost 1 and half years working with brush and maya sculpt tools, I have made 1308 morphs for my miracle character which is going to be used in VFX and also in Unreal. It shocked me to see that Maya, the industry software doesn’t have features which is called ERC FREEZE. So basically it’s a Da3d term where  blendshapes also moves bones. To explain this feature, let’s look at bones. Bones move parts of the model via paint weight information. The ERC freeze in Daz do the reverse, ie when model parts are moves via blend shape bones move. Now you may ask why I need that. I made the many of character faces where jaw is narrowed or face is just longer like Arians etc. That’s why I want to move my bones as my blend shape changes the face looks. Also this has to be done to work with aim constraints for eyes to look at camera for scenes.    

 Now I’m giving a link where a person said that it’s possible
https://forums.cgsociety.org/t/how-to-make-rig-to-follow-the-full-body-blendshape/1774709yay.          Now, where that BindPreMatrix exists and how to make that custom rigging possible???

[jmreinhart]

That link you've posted appears broken. 

The bindPreMatrix is an attribute on the skinCluster that stores the worldInverseMatrix of the joints when you bind the skin. It needs those value because it compares where the joint was to where it is now to know how to deform the mesh (https://www.youtube.com/watch?reload=9&v=-alM6DmfpNA) this video gives a more in-depth technical explanation. 

Using bindPreMatrix is really cool but requires quite a lot of setup. If you are trying to do some sort of character customization (which it sounds like you might be) it's probably better to have the character parameters drive the joints to get most of the deformation and then just use your sculpts to get the extra change you can't get from the joints alone. The blendShapes would be driven by the same character parameters as the joints. 

https://animatorsresourcekit.blog/2017/03/20/morpheus-rig-v1-0-free/  The morpheus rig is a good Maya example of what you are trying to achieve.

Most game engines don't keep the bindPreMatrix connections when you bring the rig into the engine.

[Anonymous]

Thanks you very much for the quick reply. I can feel it that a lot of work is need and also my knowledge about this part is limited. I wil try the rig you gave me. Now the most important thing is I am ready to pay to learn also if someone hp me out with his own solutions. It's true that most of engines don't support it but hey there is where we need to add module. 

Id be grateful to you if you help me out with this stuffs. I can tell you my skype id if you would . . You can feel my condition right?? T__T i spent too much time on morphs. I just want to use it fully

[jmreinhart]

Id be grateful to you if you help me out with this stuffs. I can tell you my skype id if you would . . You can feel my condition right?? T__T i spent too much time on morphs. I just want to use it fully

I can answer specific questions if you have them but I'm not an expert in this particular area so I can't step you through it.