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Aswin B avatar image
Aswin B asked ·

C4DtoA - Hair color from texture

Hey all,

I'm using Arnold core 5.0.1.4, C4DtoA 2.1.2, and the method to color hair was different in older versions of the plugin.

I've added an Arnold Parameters tag to my Hair object with 'Export UVs' checked. In the Hair object, I plugged in the geometry's UV tag to the UV parameter in the 'Advanced' tab. But the hair still renders black when I plugin an image texture to Base color or diffuse color of the 'standard_hair' shader.

Am I missing a step? Could you please outline the steps to generate hair, colored based on the texture of a given object?

Thanks!

c4dtoacolorhair
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thanks so much for the post it really saved me :)

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Peter Horvath avatar image
Peter Horvath answered ·

That should be it. Enable 'Export UVs', set Diffuse weight to 1.0 in the hair shader and connect the texture to the Diffuse color.

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...and thanks for the answer :)

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Peter Horvath avatar image
Peter Horvath answered ·

Use a user_data_rgb shader with the display_color attribute. Check out this tutorial:

https://vimeo.com/139620806

The noise (or any other texture shader) should work fine until it operates in the UV space.

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Peter Horvath avatar image
Peter Horvath answered ·

Each hair needs one vertex.

You mean colorize clones by a vertex map? You can access the display color of the clones in an Arnold material, so you can do what C4D allows. Maybe there's already a solution to control the display color by a vertex map? Or could be achieved with a custom Effector maybe?

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Tobias Gremmler avatar image
Tobias Gremmler answered ·

Perfect, many thanks!

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Tobias Gremmler answered ·

Cloner display color to Arnold material? How is this possible? Btw, just tried to colorize the hair with a noise, but this doesn't work either. So for now only texture can be used for topologically coloring hair, right?

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Tobias Gremmler avatar image
Tobias Gremmler answered ·

Thanks for the prompt feedback Peter! So each hair needs one polygon, right? That would require a pretty dense mesh. But for in some cases, it would be really helpful. Btw, could this feature also be applicable to clones? It would be great to have the possibility to colorize clones or hairs more selectively :)

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Peter Horvath avatar image
Peter Horvath answered ·

Right, vertex maps don't work at the moment, because they are exported to the polymesh and not the curves node. I can fix that, but note that the number of data in the vertex map has to match the number of curves.

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Tobias Gremmler avatar image
Tobias Gremmler answered ·

I'm trying to do this with a vertex map instead of a bitmap. the vertex map comes from the same surface as the hair. But it's not showing any color change of the hair. Maybe there is a node that can convert the vertex map node output into a bitmap/texture format which can be interpreted correctly by the hair? It has to be on the fly (no texture baking), because the vertex map is changing gradually.

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Aswin B avatar image
Aswin B answered ·

Ah, I hadn't set Diffuse Weight to 1.0. Thank you Peter!

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