Metahuman LOD Skin cache?

Development Rendering
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1

I tried to export metahuman head to fbx model, and then import it to UE5. Then I found that the eye blink is so strange.
I found that in metahuman head mesh, there is an check box named “skin cache usage”, when I disable it, the eye blink comes to be strange the same as import from fbx file.

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So, How does this skin cache work?
When I import the head fbx, even I check that item, the eye blink is still strange!
Did I miss some point when import or export the mesh~~~

2

Hi, have you found a solution? I’m facing the exactly same problem.

I was able to somehow fix it by setting the cache option to enable (it’s auto by default) on imported head model, but the interesting part is that the imported model was a copy of original metahuman head that i have previously exported from unreal. To make this clear here is step by step what exactly i have done:

  1. Add a metahuman using quixel bridge to your unreal engine project
  2. Export the head skeletam mesh using asset actions → export
  3. Load the resulting FBX in houdini (I used FBX Character Import)
  4. Remove LODs (I have no idea how to include all LODs using houdini to a single FBX) and clean up “Animated Pose” output hierarchy.
  5. Export the result (LOD 0 in my case) to an FBX file using FBX Character Output node
  6. Import the resulting FBX file into unreal (select archetype skeleton and archetype physics asset, check blend shapes import, uncheck creation of new materials etc.)
  7. Open up the resulting asset and and set correct materials, material channels (there are few materials that are using green channel), animation and post processing blueprints
  8. Import *.DNA file of the source metahuman (the one we have imported from quixel bridge) and select the skeletal mesh that we have got in step 6.
  9. Set the cache option to enabled.
  10. Save everything & check the control rig by changing default preview asset to the head we have imported, it should be perfect.

My problem is that this is not working when I first import a metahuman into maya (using quixel bridge & maya plugin) and then export it into houdini where I’m making some cleanup & adjustments (not working even without adjustments) and then import the head into unreal. In this case the skin cache option has no effect :frowning:

I have found, that this issue has something to do with world normals (check unreal buffer visualization), but I still have no idea what exactly I have to do in order to fix it, or what exactly is going wrong.

3

Looks like I have found the answer. It’s the vertex color & precomputed normals. I have no idea how we should calculate these, but copying these values from UE exported mesh onto maya mesh fixes everything.

4

Hello,How to import the vertex colors and pre-calculated normal lines in UE into maya, can you tell me in detail? I have encountered the same problem now, and the exported FBX in UE is different from the original file grid in Maya

5

Sory, can’t help you with this, as i have done it in houdini, but i’m pretty sure that maya has such functionality

6

Hi,all, as we can see, there are so many implicit and explicit settings to import a fbx in UE as metahuman skeletalmesh. I have wrote a plugin named DNAupdater, you can use the UE official DNA calibration toolbox to modify DNA file in maya, and then use my plugin to apply your modifications directly into UE skeletalmesh. No fbx anymore.