Has anyone experienced this issue with Houdini Groom Cache imports in Unreal?
I’m working on a Houdini → Unreal groom pipeline for cinematic hair, and I’m running into a really confusing problem with Groom Cache importing.
A few days ago, I successfully imported an animated groom cache into Unreal with no issues. Unreal created both:
- Groom Asset
- Groom Cache
Everything worked correctly.
Now, using almost the exact same workflow and export settings, Unreal behaves differently.
When importing the Alembic, Unreal DOES still detect it as a Groom import.
The Groom Import Options window appears normally, including the Groom Cache import settings and frame range options.
I can:
- enable Groom Cache import
- set the correct frame range matching the Alembic
- proceed with import normally
BUT after hitting Import:
- Unreal only creates the Groom Asset
- absolutely no Groom Cache asset gets generated
- no error message appears
- the cache just silently fails to exist
The Alembic itself definitely contains animation data:
- Houdini reads the animated curves correctly
- Blender also detects the geometry cache/animation properly
I tested this in both UE5.5 and UE5.7 and the same issue happens in both versions.
Things I already tried:
- Exporting as Ogawa
- Using Labs Unreal Groom Export
- Exporting curves only
- Re-exporting multiple times
- Verifying frame ranges
- Clearing DerivedDataCache
- Testing fresh projects
- Checking topology consistency
- Using Hair Generate output
What confuses me most is:
The exact same workflow worked previously, including successful Groom Cache generation in Unreal.
Now Unreal still recognizes the file as a Groom during import, but silently refuses to actually create the Groom Cache asset afterward.
Would really appreciate any insight from people experienced with:
- Houdini Groom
- Vellum Hair
- Unreal Groom Cache
- Animated Alembic Curves
- USD / Groom workflows
Thanks!