How to integrate a rigify rig with a MMD armature?

I have a MMD character that I want to make the animation of easier through generating a rig with Rigify.

The unique problem is that this character must remain MMD compatible even after a rig is generated. This means: the bone’s of this character must not added/removed/renamed/repositioned/reweighted/re-parented in order to retain their compatibility(so the animation on their bone’s can be exported and easily re-applied to other characters that share the same MMD bone-set).

An older 2015 solution to this is(using the google translate website translation): however as the pitchipoy armature in rigify seems to be no longer a part of rigify, I receive an error when trying this in blender 2.79(the version the code in the website is written for) stating that the pitchipoy architecture could not be added.

Does anyone know of a solution(ideally in blender 2.8) to integrate a MMD rig with a rigify armature?

For rendering in Blender, or rendering in MMD?

For rendering MMD animations in Blender, weight the mesh to a rigify rig, and give rigify control bones costraints that copy transforms from an MMD rig (or from bones that are parented to bones in a default-ish MMD rig.)

For animating in Blender and outputting to cross-model compatible animations in Blender, instead have an MMD rig that uses constraints (likely copy transforms) to copy from the Rigify rig to the MMD rig, then bake the action.

@Daryl_D_Souza @bandages
I created a tool to integrate MMD and Rigify armatures.

If you are interested, please try it :wink: