ParticlePositionWS not working

I have a basic particle system and material (set up the same as the official tutorial video) and I’m unable to get any particle system input nodes to work (other than particle color). Particle Position, Age, and all other ones seem to just return 0 (or vector 0,0,0) no matter what the state of the actual particles are. What do I need to do to make these work?

Hey bwiklund -

When you say just return 0 or (0,0,0) are you referring to Cascade or the Material Editor? The viewports for each of those editors do not preview World Space Nodes as there is no reference to pull from and they will always return a 0 value. You should however be able to add the particle system to your level and see the effects of the nodes there. If you can let me know what exactly you are trying to do I can run a more specific test for you.

Thank You

Eric Ketchum

This is in the level as well.

Hi bwiklund -

For Particle Position WS (World Space) to be effective in most purposes, you will need to take Particle Position and Subtract Actor Position which will yield Local coordinates or more precisely the world position information centered not on origin, but on the actor’s position. I am continuing to look into the other Particle Nodes as well.

Thank You

Eric Ketchum

I’m not having a problem with the offset of the position, I’m just not getting position at all.

This is on OSX, 4.7.3, btw.

Hi bwiklund -

There does appear to be a problem with the Particle Position Node on OSX. I have placed a bug report in, for reference UE-12251, as our investigation toward a solution continues I will let you know.

Thank You for your help tracking this issue down -

Eric Ketchum

Thanks, good to know.