Alembic Import have wrong transforms

Unreal 4.13 - 3ds Max 2016 - standard ABC exporter.

I am having all sort of weird transform behavior when importing Alembic to unreal, I often get a flipped Y axis, sometime a 90 degree rotation on the X axis.
I exported a static mesh version with fbx as a reference. It comes in perfect
I exported Alembic static frame, this one is 90 degree rotation on X axis and flipped scale on the Z axis.
I exported point cache version animated, this one is 90 degree rotation on X axis and flipped scale on the Z axis.

*The ABC files reimport properly into Max.

But what puzzle me most, is I have an asset exported the same way with alembic that only has the flipped Y scale. (Not the Z like the other tests.)

Is there an exporter for 3ds max that provides more options that you guys are using?

Hi Marc,

We are looking into supplying an option to specify your handedness during import. Would you be able to upload the model you used for testing purposes (it looks awesome btw!).

Cheers,

Jurre

Hi Marc,

I’ve gone ahead and entered the ticket for this that you can track here: Unreal Engine Issues and Bug Tracker (UE-35510)

Thanks for the clear steps and comparison.

Tim

HI Tim, in the ticket you noticed the rotation but I also encountered a flipped axis in scale. Just want to make sure its tested with an asset that has a distinctive “Forward” “backward” recognizable features. cheers.

I essentially made your test asset in 3Ds Max for testing purposes and attached to the ticket. (Agreed that it is a cool test asset to quickly identify things like this!)

Good catch on the scale as well. Thank you! I’m updating the ticket now and including an image of that as well for Jurre.

Hey Tim, the uvw channel are also flipped on the V coming out of 3dsmax.

Looks like Jurre is already looking at a similar question here: Alembic UV - Pipeline & Plugins - Epic Developer Community Forums

This is an absolute requirement. It was fine not having said option for FBX because it is axis aware and can adjust itself, but Alembic can’t do that and many applications use different coordinate spaces.

Thus the ability to specify an import transform should not be considered a nice optional thing, it is a requirement. Ideally, this will allow proper transform conversion from any source coordinate (left or right) and axis orientation. Additionally an option for scale and additional rotation would be very nice to have.

The ticket you reference seems to be specifically about Max, but please bear in mind that different DCCs use different coordinate systems. Making it work properly for Max will just make it then be wrong for Maya or Modo. This needs to be user configurable. Having easy selectable presets for the various DCCs would be great but the user needs to always have the option to manually set up a proper transform as well.

Just wanted to confirm I have the same problem coming out of Maya, on all of what you guys discussed. Y-up, X axis flipped, and V axis flipped. There is an option in Maya to have the Z up I have not tried it however as my scene was already setup with default Y-up