I am working on a third person template game now and my purpose is to create characters with facial animation for cinematic and game runtime with low cost. After researching into facial rigging and face weight painting I found that the easiest way to achieve facial animation is to use/reuse metahuman, reuse its facial animation.
That leads to purpose B: I want to turn my other characters(from other games and mixamo) into a rigged metahuman. I currently uses houdini to prepare character meshes, and I decide to rig characters in metahuman standard in DCC rather than using Epic MHC online services ( a. because my character mesh is already there and it is what the game designer appointed, I don’t want another AI-figuring to decrease the accuracy of the original character mesh. b.My character uses a simple skeleton, I don’t want to use MHC’s complex body skeleton)
However, when I start to look at metahuman, its complexity does not make life easier.
And moving on I start to come across problems.
**Issue 1.**I found this link on creating controllable 3rd person metahuman.
I found that all metahuman blueprints seperate character mesh into 5 or more parts.
The torso is a seperate mesh, the legs is a seperate mesh and the head is a seperate mesh. And the entire metahuman skeletal assets are
My questions is: A1: how and why is the body disintegrated? Sure, I can export my character meshes in houdini and in different parts and files. But…Isn’t that leaving a seam between each pair of components? That may have issues when limbs are bending in extreme angles. A2: Since head is also a sperate mesh, and unlike torso and leg meshes which could be combined directly because torso and leg uses exactly same skeleton, how can it be combined with the rest of the body? They aren’t even using the same skeleton, the head uses a unique skeleton which does not contain lower body skeleton but contains extra face skeletons.
Issue 2. So in order for my character (let’s call it Bob) to be able to use metahuman’s facial animation I have to rig it into metahuman head skeleton standard. But when I found the skeleton of the face I think that it is impossible to rig it. There are so many head bones! I cannot remember which bone should control which polygon in my character’s head !
A1: Metahumans can be customized with different clothing, so having separated skinned mesh is an easy way to swap them based on what you choose in MetaHuman Creator.
Not sure if they have a unique mesh with a unique skinning, and then simply transfer the skin weights based on your selection, but the skinning is consistent between different pieces of clothing.
A2: The head has a barebone body skeleton, that’s because the head follows what the body is doing, and the joint of the face are driven by the actual facial animation.
If you take a look at the AnimBP of a Metahuman face, you’ll notice that there is a Copy Pose from Mesh node, which takes the animation data from the body and applies that to the head, then you have a Layered blend per bone, which pretty much separate the incoming data, so that the body animation is applied up to those joints ( neck, facial root ), and everything above that is driven by the face Control Rig or your standard animation sequence.
Also the Face is a child of the body, and because of the Master Pose setup in Blueprint, it will follow the body, along with the body animation from the AnimBP setup.
Issue2: Best way to have a fully rigged face based on Metahuman’s skeletal structure is to use the Mesh to Metahuman tool in Unreal engine, there are plenty of tutorials about it.
Then you can download the source file for Maya, so that you have the rig ( anc Control Rig ) in Maya as well.
QuestionB: Based on LODs ( both in Unreal and Maya ), corrective joints from the face are removed, so the face skinning is simpler.
Only LOD0 has all the joints, LOD1 and so on have less and less joints influencing the face.
Hello, thanks for your fast and detailed response.
I kinda get to understand the thing a little bit. Seems like it relates to the concept of modular skeletal mesh component?
(Modular Characters in Unreal Engine | Unreal Engine 5.0 Documentation)
As for Question A2, so if we seperate head skeletal mesh with body skeletal mesh, then they have to use two seperate animation blueprint ? I searched about the combing head and body animation of metahuman on youtube and found them talking about Copy Pose from Mesh node. But when I downloaded sever metahuman I found that there is no such setup in my metahuman’s face’s animation blueprint.
