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Making Particle collapse by near distance

Hello,
We all know how the draw distance will make a particle system not render in the distance. LOD will help us design far system and make them more efficient as well.

What about Near particles?

What if I would like particles to fade when they are close to the player camera (easily done in the material) , but what if I want to make them collapse to a single point when I get close to them as well. I thought that would help with overdraw and fillrate.
I visually can achieve this with the following nodes in the material(Works great with geometries by the way):

Now the question that I have for you smart people, is why do I still see the particle in Wireframe view or Shader complexity view?
The opacity in both the material and the particle system are set to 1.
Does Unreal apply a different shader to the particles when it goes into Shader complexity and/or wireframe?
Is this totally useless and will not help with performance at all?
Should I only worry about opacity?

help would be much appreciated :slight_smile:

What you’re trying to accomplish will definitely work, people use WPO to collapse particles all the time. I’m not able to reproduce your issue with seeing the particles in the shader complexity view, when I use a collapsing material on a default cascade emitter, nothing gets rendered in the overdraw or shader complexity views, they’re empty, just as they should be.

The particles do show up in wireframe view, I’m not sure why. Perhaps WPO is not applied to particles in wireframe (seems to work on static meshes though). I wouldn’t worry about seeing them in wireframe though.

This is what I tested with, in 4.24.1 using the default cascade emitter.

Cool, thanks for testing it out @Arkiras ! I’ll test your setup if I have time today. I’m wondering if the shader complexity has issue with the lerping (which I don’t really need for this) on the WPO.

Thanks, useful :slight_smile: