wetmaps

[FishB8]

Has anybody tried (or have any ideas) on how to implement wetmaps in Blender?

If you're not sure what I'm talking about, wetmaps are a means to change the color of a surface when a fluid touches it. It reatains the changed color even after the fluid is gone until it "drys".

[z3r0 d]

so it's a stencil texture?

[FishB8]

It could be done using a stencil texture, but the source for the stencil would be the tricky part.

It would have to stencil whatever the fluid mesh touches, and then it would have to fade out over a duration of time set as the drying time once the fluid mesh is no longer touching it.

You might be able to create the stencil input by hand, but that would take forever.

[kattkieru]

You could use an empty to set the height of a wetmap on a character by setting the map's coordinates to the empty and making sure the map doesn't repeat / extend past its original texture size. That way if you raise the empty the map raises with it, so it'd be useful for situations where the character is standing in rising water, etc. Something similar could be done using an alpha map parented to an empty, effecting the spec, color, and reflection channels of a texture.

Rain'd be different; you'd essentially need some way to animate the map such that little splotches come in at first and then the character becomes soaked. A program like Motion or Particlillusion (sp?) could do the spattering fairly easily, but doing the same in blender is beyond my knowledge.

Hope that helps. If you come up with anything neat give us a look.

[FishB8]

That's a really good idea for when somebody is wading in water, but I'm trying to figure out a solution for a situation where the area touched by the liquid is not so predictibly linear.

As you can tell from this jpeg, it looks kind of odd when the water doesn't wet the cement that it touches.

[David Mcsween]

What you need is an after image of the water path to use as a stencil (or matte shape). Try rendering a top view of the concrete obj. with water on it maybe retexture your fluid black and the concrete white. Just do one frame that has the complete water flow, then orco map that back onto the concrete.