Alembic cache offset issue?

Hey everyone,

I have run into an issue while importing Alembic caches for our character’s clothing. These files are to be used in sequencer and should line up with character animations they were simulated on top of. However, I have found a strange transform offset which seems to effect the cloth’s location, rotation, and scale in Unreal. You can see the example here:

OffsetIssue

Back in maya the cloth follows the character perfectly. But in engine the scale is completely different for the movement. Strangely, the cloth scale itself doesn’t seem to be effected. I can move the cloth and line it up pretty well with our character but have no way to scale or offset it in engine to work correctly.

We already have checked the following:

  1. Exported frame rate
  2. Maya vs Unreal scale
  3. Alembic export settings like World Space
  4. Unreal import settings like Merge meshes / Bake Matrix / Conversion presets

Has anyone else run into this problem before? I have older cloth files that do not have the problem with the same import / export settings. I can’t imagine why it would line up in Maya but then once exported, have drastically different transforms.

Any help is appreciated! Thanks!

1 Like

same problem here

same here, no solution

Same! I have not found the solution. I have been looking at MD time step. I’m wondering if there is a way to fix this with that. I don’t know though. I’m very confused and trying to research this as well.

here is my study,
Unreal will compress or compute the ABC animation to “unreal format” to make it lower size~
It will lose the accurate position between frame by frame.

here is my study,
Unreal will compress or compute the ABC animation to “unreal format” to make it lower size~
It will lose the accurate position between frame by frame.

The same here with animated hair as alembic exported from Houdini. Roots of the hair change position when they should not do it.

Bump! I have the same issue with a character.

did anyone found a solution for this issue ? i have it from time to time.
the exported base anim from Unreal and the new abc cache matches perfectly in Houdini. but adding the abc to unreal gives me an offset

Having same issue, looking for a way to tell unreal to have 1 by 1 frame value in the timeline. My 600 frame sim from houdini is auto compressed to 150 frames in the timeline. Its maddening

I’ve found a solution for a Marvelous Designer to Unreal MetaHuman alembic cache. Mine were offsetting in the sequencer when imported too (I even checked in Blender and it seemed alright in Blender too so I knew it had to do with Unreal 5.2)
This dude is a life-saver, works great! - https://youtu.be/gH_kExD4fFM?si=I7zInQuwATZqP-0N
Maybe it can help understanding with other software alembics too as the post-process on the MetaHuman needs to be applied to the character before exporting as he shows here in the tutorial
Also its super important that you match your framerate in EVERYTHING