Procedural gradient falloff shading for a simple path
I'm trying to build a system with which I can have any sort of geometry (mostly planes) the edges of which fade off into full transparency. Right now I'm simply using a black to white vertical ramp and mapping the corresponding faces to it white using a different shader on the 'path'.
This has a few obvious issues:
a) lots of hand authoring of edge meshes and their UVs, time intensive
b) not very flexible
c) can't deal with multi-directional falloffs (see below)
So, how would I go about setting something like this up in Unity? The the ideal scenario would be to have a system by which I can only author the path itself and generate the falloff edges based on a selection. Is something like that possible in Unity alone or would I have to use a hybrid approach where I generate the meshes in something like Maya and just do the shading here (I could automate that for the most part, but I'm still stuck on the shading part) ?
This has a few obvious issues:
a) lots of hand authoring of edge meshes and their UVs, time intensive
b) not very flexible
c) can't deal with multi-directional falloffs (see below)
So, how would I go about setting something like this up in Unity? The the ideal scenario would be to have a system by which I can only author the path itself and generate the falloff edges based on a selection. Is something like that possible in Unity alone or would I have to use a hybrid approach where I generate the meshes in something like Maya and just do the shading here (I could automate that for the most part, but I'm still stuck on the shading part) ?
Replies
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You might be able to detect edge vertices, and apply vertex colors to them. So the gradient is vc not texture.
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Ah, great idea, I'll give it a try! Though I'll have to figure out a way to distinguish border edges that I want soft vs ones I want kept straight...
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OK, gave it a try, it's a good idea, works great in most cases and super easy to author. But the point where two gradients start intersecting becomes a problem because I cant get a smooth transition between the two gradients. Changing the geo/tessellation helps, but seems to shift the issue, not get rid of it completely.
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You might also try using the UV itself as a gradient. Similar resolution issues, but in authoring you have finer control over the rotation & scale.
Shader Forge has examples on their site about how to use the UVs as a gradient. -
I'd recommend possibly setting your gradient to an unlit shader as well. It will help with the sharp edges. Or if the plan is for the gradient to be replaced with a different texture later get your smoothing groups sorted. You can also relax that corner vert before before tessilation, should give you a more radial gradient if that's what you are looking for.
