Hair: Creating White and Light-Colored Hair
Realistic white or light-colored fur or hair can be fairly difficult to achieve. You can use the Hair Renderer shader that is applied to hair by default, use the Hair Geo shader for more control over how color and transparency are distributed along the hair strand, or try out the MuhHair shader MuhHair Shader (http://www.xsibase.com/tools/shaders.php?detail=894) written by Daniel Rind. This shader can give you quite decent results and tends to render faster than the XSI hair shaders.
Here are some general tips to help you create white or light-colored hair:
- White hair is not white: it’s chromatic gray. There are lots of tints of “off white” in white, but if you have the color turned to pure white, you won’t have much variation. You can use the Color Variation option in the Hair Renderer shader to achieve subtle color changes. You don’t want to fill up the whole color spectrum range with the base color—you need to allow a little room for the specular color (which is additive). The white should be brighter than anything else in the frame, so make sure your subject and background don’t compete.
- White hair is self-illuminating in that light bounces all over the place inside. There is very little diffuse range, which means that the hair’s shading is mostly the base color—anything else comes from shadows. You can set the Use Blend Gradient parameter in the Hair Geo shader so that it’s mostly Ambient (about 85%) to diminish the effect of the diffuse shading. In other words, the shaded hair (pre-shadow) is just the base hair color with no dark-to-light variation. The rest of the shading comes from the shadows and specular value. It’s not ambient in the traditional sense because the setting doesn’t affect the shadow density.
- Use lots of hair strands (Total Hairs value) that are very transparent. This allows lots of light to pass through the volume, giving a nice fluffy appearance (if you’re trying to create fluffy fur).
- Try applying multiple instances of hair to the same object, each with different density settings (if it’s fur): one that’s long and loose (low stiffness, higher frizz), and one that’s short, dense, and stiff.