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Growing Hair with Gradient Map
I have a texture, which has an animated gradient map slowly growing across a the face of a letter. As the gradient map is animated, the colors change and it works fine.
I’m attempting to add hair into the mix. My thought was that I could use the same gradient map and apply it to the Length parameter and have the hair be revealed with the same mask. I’m having difficulty getting the gradient map to align as it does with the texture. It seems like it would just align the same way, but it appears to be way off.
Any ideas?
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6 Replies
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I just tried it here and it worked fine. You say your gradient is using colors? The texture input in the hair material is only looking at luminance levels, so maybe that’s it. How are you animating the gradient? Via that material or texture tag? What gradient type are you using?
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Thanks Adam- I think maybe something is up with my texture mapping? I’ve uploaded a file that illustrates the issue I’m having. It seems to work fine on a plane, but on my text there’s an issue.
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I’m not seeing the file.
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Sorry- try this: 9021_test.c4d.zip
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Interesting. So it seems that the hair material can only use the base UVs of an object. Since your color gradient on the C object is centered/scaled via the texture tag, the shaders used in the hair material don’t match (since they can’t be offset/scaled the same way).
The only way I can think to fix it would be to adjust the object UVs and/or the gradient so that it fits the way you want it without using the offset/scale parameters in the texture tag.
The easiest way to do that would probably be to delete the existing UV tag, set the texture tag to use flat mapping, and move/scale the flat projection to get it the way you want it. Then, right-click on the texture tag and select “generate UV coordinates” from the context menu. That way the color material and Hair material will use the same coordinates.
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Thanks for looking into that- I just tested that and it seems to be a good work around. I guess in the future the more precise way would be to use vertex maps in cases where you really want to control growth in particular areas, but those are a little more difficult to animate. I’ll have to do a little more research on that method. I know there are a few Xpresso setups and Python scripts out there, so I’ll explore that option a bit more.
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