Hello,
As part of developing a character customization system for our upcoming project, our studio is currently experimenting with the features of the Mutable plugin. Our goal is to enable facial customization for our avatars.
However, we are facing a major issue: facial morph targets do not work correctly on MetaHuman heads when the “Reshape Skeleton” option is enabled. Despite multiple attempts—including the use of RigLogic DNA and constant DNA files—the problem persists, and Unreal Engine 5.6 consistently crashes during Character Object compilation in Mutable with this configuration.
Below are some precise technical details regarding our setup:
We apply, via a mesh reshape, the morph deformations from a secondary mesh (which contains only the deformation morphs) onto a MetaHuman mesh. The skeletons, skinning, and vertex order are strictly identical between these meshes.This approach allows us to take advantage of the “Reshape Skeleton” feature provided by the Mutable node.
The Mutable structure for the head is as follows:
-
The mesh reshape receives:
-
Base Mesh: a skeletal mesh generated by MetaHuman Creator.
-
Base Shape: a mesh with identical topology but with morph targets disabled.
-
Target Shape: the same mesh with morph targets enabled.
The mesh reshape is then connected to a Mesh Section, and subsequently to a Mesh Component where the skeletal mesh from the Base Mesh is assigned.
The same structure is used for the body mesh.
**Observed issue:**When the “Reshape Skeleton” option is enabled, the applied deformations only partially match the Target Shape. Visually, the facial morphs appear incomplete.
Our tests suggest that this issue is specific to MetaHuman facial meshes, likely due to limitations in how bone transformations affect the final deformation.
When “Reshape Skeleton” is disabled, the morphs are rendered correctly.
On non-MetaHuman meshes, enabling this option works without any issue.
The same process applied to the body mesh works perfectly.Additionally, using RigLogic DNA together with Mutable in Unreal Engine 5.6 causes the editor to crash systematically.
We would like to request your assistance to:
- Understand the possible causes of these rendering inconsistencies when using “Reshape Skeleton” on MetaHuman facial meshes.
- Learn whether there is currently a known solution or recommended method to work around or resolve this issue with the current Mutable version.
- Know whether future updates to Mutable are expected to address this incompatibility.
- Determine whether the crashes related to RigLogic DNA are caused by our current usage, and what the proper integration workflow would be.
Thank you in advance for your time and support.
Kind regards,