New Alembic Plugin Testing

Howdy, I’ve been testing out the new Alembic importer plug-in in the 4.13 preview. So far it seems like a feasible option but I’ve encountered a few issues. Some I can work around and some I can’t.

First, certain animated caches immediately crash the editor when I import them as geometry cache. I can’t provide the cache here for sake of information security (its any character cache) but I may be able to create a simplified non-sensitive example case. Unfortunately, the crash does not provide the standard bug report dialog.

Second, applying a shader to a geometry cache with the “PN Tessalation” mode breaks down in the render. Here is a screenshot of a geometry cache sphere with a solid white shader.

Third, the “Materials” section of the GeometryCacheActor details works as expected however if I save the level then close and re-open the editor this section usually disappears, this also usually breaks material assignments.

Related to this I’ve noticed that opening a geometry cache in the asset editor shows a “Materials” section but does not allow assignment. Only assignment to the actor is possible. Is this by design?

I’m still fairly new to Unreal and the editor so some of these issues may be me a problem with my work flow. Let me know if other information or materials will help.

Hi Ryan,

Thanks for the feedback and raising the issues you’ve found!

I’m interested in the crash you’ve found, but we have made quite a sum of fixes since Preview 1 so your issue might have already been fixed.

As off now the Geometry Cache asset does not support an adjacency buffer which is required for the tessellation setup, in this case you could choose to import the animation as a skeletal mesh with morph targets (also a more compressed way of importing) which will support tessellation. :slight_smile:

I’m going to have a look into the materials issue and will report back to you with what I’ve found!



Thanks! I tested out the caches that were crashing in Preview 2 and they imported without error so I think we’re good on the front. Also, the lost material assignments seems to be happening only for shapes that lack texture coordinates, so that’s not much of an issue, though the general material assignment weirdness is still a problem in Preview 2.

Sorry to badger but preview 3 still has the same material assignment issue. Stability looks good though.

Indeed, thanks for the update.

Sadly a fix for the material assignment will make it into the engine soon though since we released 4.13 yesterday it is too late for that. I will update this thread when there is a fix in!