Visual Effect Graph - pCache Attribute Map (split components) and particle shadows

Hi, I am new to Unity's new Visual Effect Graph editor. Though I have used similar systems for many years.

My project is using Unity 2019.3.3f1, Universal Render Pipeline (URP)


I have 3 questions:


1. Can I use custom mesh with my own shader (URP)?

2. Is there a way to split the pCache Attribute Map (3d texture) into separate RGB channels, so that I can use these for different particle manipulations? Position, size, color tint

I want to use red vertex color area to spawn submesh mask1, green for submesh mask2, blur for submesh mask 3, and so on.





I can only seem to spawn grass particles on the red vertex color channel


3. Is there a way to tint grass particles that are spawned in shadowed areas? E.g. by looking up light map pixel below, to the nearest particle pivot, and tint the grass by this value.If a grass particle is half way in light and half way in shadow then it will use the tint from where the pivot is. Or is there another method? I understand that GPU particles are unlit on URP?




Please advise!

 

To split the RGB you could try setting it as the particle colour, then using get attribute colour for the components, and finally resetting the particle colour to whatever it is meant to be. I've been told that the order of operations in a context is linear from top to bottom so this kind of trick should work...

 

Thank you, that sounds like an interesting workaround. I will try that out!

 

Using the 'Get Attribute Color' and resetting the color on Ouput worked! Do you know if particles are automatically culled when they reach size 0? Or do I need to use some kind of a Size Test to kill particles below a certain size?