Export simple FBX animation to Unreal Engine

[ydyd]

Hi everyone!

I'm struggling since days with something should be in my opinion simple, but can't find a solution.
I have a Cube in Houdini with transform keyframes, basically moving and rotating, which I want to export as an FBX to import it in Unreal Engine.

When I check the FBX I export on other softwares, it works perfectly. But Unreal Engine doesn't read the animation, it always import it as a static mesh with an animation that is not moving.

When importing to Unreal I create a skeletal mesh and import exported animation frames. And afterwards I select "use animation asset" in the mesh and select the animaiton but doesn't work.

I know sounds very simple but I'm going crazy and been reading tons of threads but can't make it work.

Any support would be very much appreciated!

Thank you!

[Atom]

If your cube doesn't have an armature associated with it, creating a skeletal mesh will have no effect. Otherwise, add a single bone to your cube and animate the bone, not the mesh. For boneless mesh animations, try using the Alembic file format and import to Unreal as a geometry cache.

[ydyd]

Hi Atom,

Thank you for the response! I see, I thought was possible and that Unreal would generate the skeletal mesh if missing. Makes sense.

The cube I was using was a test, because actualle the animation I want to use has 3 cubes that are moving around independently. In this case I should create one bone for each? And instead of animating the cubes in houdini I should animate the position of the bones?

Not sure if there's an easy way of creating a single bone in Houdini, as I've never used them. If there's any hint or link you think would be useful, would be very useful.

Thank you thank you!!

[ydyd]

The alembic workflow worked, but after a bit unreal crashes. I guess that this caches a mesh per frame and makes it really heavy?

[skomdra]

On 7/1/2022 at 3:21 PM, ydyd said:

Hi Atom,

Thank you for the response! I see, I thought was possible and that Unreal would generate the skeletal mesh if missing. Makes sense.

The cube I was using was a test, because actualle the animation I want to use has 3 cubes that are moving around independently. In this case I should create one bone for each? And instead of animating the cubes in houdini I should animate the position of the bones?

Not sure if there's an easy way of creating a single bone in Houdini, as I've never used them. If there's any hint or link you think would be useful, would be very useful.

Thank you thank you!!

Yes that is the best way, if you have something as simple as animating cubes, look into https://www.sidefx.com/docs/houdini/nodes/sop/kinefx--capturepackedgeo.html and use ROP FBX Character Output. Alembic for this case (if you have non-deforming geo) is an overkill.