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I can't figure out how to make my effect sample from an animated skeletal mesh in Unreal 4. I'm at a complete loss. If I assign a static mesh to the mesh property of the imported asset everything is fine.

But if I assign a skeletal mesh everything collapses down to a single point:

Also, what is this thing and what is it used for?

What should I be doing that I'm not doing to get to the point where I have particles sampling from an animated, skeletal mesh in Unreal?

by feanix (1.2k points)

1 Answer

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Hi feanix,

Skeletal mesh sampling was already implemented in the plugin using UE4's CPU skinning, but had some issues with some meshes. So on your side it should already work, a few things to know how to make this work:

- Skeletal mesh sampling is achieved through Attribute Samplers

- Attribute Samplers can only be used (for now at least) at particle spawn, that means, in the Spawner Script: You can't samplePosition/Normal/... at particle evolve

- This can be performance heavy using the UE4's CPU skinner

So we just finished experimenting with our own CPU skinner, and this experimental feature has just been merged with the development branch, which means that it will be released real soon. You should be able (even with the version you have) to follow this wiki link and find more about the skeletal mesh sampling:


So what you will need to do:

  • Spawn a PopcornFXAttributeSamplerSkeletalMesh in your level
  • Setup this actor correctly (pickup the target skeletal mesh, ...)
  • Associate this Attribute sampler with your emitter (as you showed in the previous screenshot)
  • Restart the effect

Hope this helps

by HugoPKFX (17.7k points)
Thank you. That seems to work for me now. Are the options in the following gif (Compute Velocities etc) for a future version?


I only have Use Relative Transform and Editor Build Pose available. Perhaps I need to process the mesh somehow in Unreal?

The options you see in the above link are indeed in the next public release that will come asap ;)

Basically, it allows you to specify which data you want to sample from the skeletal mesh.

You can find this new Skinned system in the v1.1.0 release that was just released.