Question About "Erosion Maps"


I’m newer to VFX so I’m still learning all of the terms and methods for how people approach making cool visual effects. I mostly use Unity (Shuriken), Photoshop, Procreate, and some other stuff, but I’ve seen what people have done using a lot of other programs.

I saw a recent post by Riot about the rework they’re planning for an older champion ‘Volibear’ on the page, they actually go through and deconstruct (presumably) one of his attack visual effects.

I saw two things that I hadn’t seen in VFX construction before, one that made perfect sense, and one that made sense, but I had never heard used, and haven’t been able to find any solid resources on it in specific relation to Unity. This is the example they posted more specifically.

It looks like a map that is used to determine what appears and falls off first based on the color channels, but I can’t find like an obvious wiki page like one might find for alpha maps, or shaders vs materials.

I would greatly appreciate any direction/tutorials concerning “Erosion Maps” but I also have a couple other questions:

  • Is there another term for an erosion map that I might just be missing?
  • On the assumption that this isn’t something currently native to Unity, would it be reasonable to assume I could write a shader to make up for this?

Also here is an example of a quick and dirty ice particle I made in Unity to practice motion. (I’m not sure how to embed stuff like this?)

Thanks to anyone who can help with this. <3

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i made a video specially for erosion. i hope this will be helpful for you.

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Thanks. This is a solid example, I may have to do some digging and tweaking to see if it works in Unity, but it definitely helps clear some stuff up. (It looks like most tutorials for unity refer to it as Dissolve instead of Erosion.)

It may not be functionality available in Shuriken unfortunately, but I should be able to get it working with some standard animation and tinkering and the shader graph.

You can get it working in Shuriken with Custom Vertex Streams Unity - Manual: Particle System vertex streams and Standard Shader support
You would need to fiddle around with shader graph to set it up.

Thanks for highlighting that workflow dev page, @Tenchu - it’s a great resource to read through! :+1:

I saw these noted before, and only ever saw them highlighted to throw errors when I was using mesh based particles, but if I can use them with shaders I can probably get them working. Thanks for the reference article.

I had to uninstall the LWRP previously because a call I was trying to make in my post processing shader wasn’t supported unless it was the default system settings, but the reality is that it locks me out of too much so I’ll just have to remake it in the LWRP.

Of course, I saw that it had a fully fleshed out display of each component and I was really curious about the stuff I didn’t understand.

I almost immediately understood the wind mesh towards the middle, but I had literally never thought to construct a mesh like that, so I need to figure out how to get a scrolling texture work in the same fashion, but it’s a really cool implementation.