Hello everyone,
This test pursued several objectives;
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Test the Metahuman workflow —> UE 5.7 (character modification and assembly) —> Blender
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Examine the possibilities of the MH character facial interface.
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Test a manual LipSync on this interface.
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Test the new XPBD solver in Blender for dynamic hair.
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In summary :
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The import from MH to Blender is very simple and works very well thru the Polyhammer addon.
The range of expressions that the MH facial UI allows and their manipulation is very broad and opens up many possibilities.
The XPBD solver responds well to the dynamics of the four types of hair used (primary strands, secondary strands, etc…).
The solver configuration for each of them, however, remains quite delicate to prevent instabilities.
As for collisions, the system reacts very well on the face. However, the MH characters are made up of two separate meshes (Face and Body) connected by continuity. The collision behavior at the discontinuity is completely aberrant even tho the normals seem to be continuous. It seems that activating the “Edge Contact” option can significantly improve this behavior, but the required resources become unreasonable. I worked around this problem by coupling a collider that broadly covers the junction of the two meshes.
Strangely, while in various tests of non-Metahuman projects, the “bake” of the hair system proceeds without difficulty, it has been impossible to bake the cache of the file inherited from the workflow used here. The cache appears as outdated, is retained if you navigate thru the animation without returning to the initial frame, but any attempt to save it either on disk or packed crashes Blender. The memory is not saturated, it seems that the problem lies in the memory management of this type of file. I haven’t had the time to analyze how the bake is managed at the node group level.
Another remark (perhaps related to the previous one) is that the residual error shows values well above 1 (100 and more) while the system remains visually stable.
I would be interested in your experiences on these matters.
