Coloring

All hair and fur has color. These colors may be solid and uniform, like simple dyed threads, or very complex, like the rich blend of colors in a wolf's coat. There's often a lot more color complexity than you think even in a simple housecat. Sasquatch is designed to let you recreate the rich color blends of real fur and hair as closely as possible.

Salt and Pepper Coloration

The most interesting property of fur color is that it is usually not a single solid hue. A fur pelt often has textured patterns, usually as irregular spots. But even within a spot there are often a blend of different fiber colors mixed together. When human hair starts to turn grey, every hair doesn't become slightly lighter. Instead, most keep their normal color, but a few random hairs become solid grey. As you get older, these grey hairs become more common until they finally predominate. This kind of mix of two different colors is called "salt and pepper" hair.

This kind of "salt and pepper" mixing of two colors is very common in fur. It also occurs in human hair, especially in dark blonde hair. It even happens in rope, since different rope fibers come from different plants. Dyed materials like yarn tend to have no variation though.Working with Sasquatch can give you strange habits. We stare at cats and dogs, study wolf pictures, and visit zoos. When you really study the fur color of animals, you see salt and pepper mixes constantly, and appreciate how rich and detailed fur really is!

Fiber colors can also vary along their length. It's especially common for the tip of a fiber to be lighter than the base. This comes from the natural bleaching effects of sunlight and water. Different colors of fibers often bleach differently. Darker hair will usually bleach more than light hair. But of course there are exceptions.. some fibers never bleach at all! And a few types may be darker at the tips than at the roots, especially if it's dyed hair that's grown.

To make similar kinds of effects in Sasquatch, you have independent color controls of "Salt" fibers and "Pepper" fibers. Each type has its own independent root and tip colors, which you select with a color picker.

Percentage and Blending

The Salt Percentage control chooses the ratio between the two. Many types of fur have only a few stray fibers of a different color. You might make this in Sasquatch by using a setting of 95%, so the "Salt" color would dominate. Or you could mix the two equally with a 50% setting. Texture mapping this attribute is especially effective. (See the S panel chapter).

Changing Salt Percentage( 10%, 50%, 90% )

Some fur styles have fibers that are a blend of the Salt and Pepper colors. Salt/Pepper Blending controls whether fibers have any intermediate shades between the two. At 100%, you'll get fibers which are mostly halfway between the Salt and Pepper colors. But at 0%, you'll have no intermediate shades; fibers will either be all-salt or all-pepper. When you have blended colors, the Salt Percentage control will bias the shades towards either extreme. In practice, animal fur has some blending of colors. Grey hairs in a black beard have almost no blending; a fiber is either light grey or dark black.

Skew and Sharpness

Each fiber has a gradient of color along its length determined by the Root and Tip Colors. It's very common for some types of fibers to mostly be a single shade with only the very tip colored differently. You can skew the gradient to make this kind of effect. Skew Color to Tip will move the color transition towards one end or the other of the fiber. At high values like 95%, you'll see almost all Tip color, with only the very bottom root set to the Root color. A low value will make most of the fiber colored like the root, and only a small area at the tip colored the Tip color.

Changing Skew Color to Tip ( 90%, 50%, 10% )

This skew is often slightly random in real fur, with some fibers showing more Root color and others showing more Tip. This kind of randomness is added with the Skew Vary control. At 0%, all of the fibers will have their color transition at the same place. Higher values will randomize the transition location, so some will be mostly Tip and others mostly Root.

Changing Skew Vary ( 10%, 50%, 90% )

The gradient along the fiber is often sharp, with the color suddenly changing from the Root hue to the Tip hue. This is especially true for dyed hair that has grown slightly. Many other types of fibers have a smooth, soft gradient, perhaps from being bleached from the sun. You can control the sharpness of this transition with the Transition Sharpness control.

While Salt and Pepper give you an enormous amount of control over the natural variation of your fiber colors, it's still not enough for some very random color patterns. Two extra controls, Bright Vary and Hue Vary offer a final way to randomize the fiber appearance. Bright Vary makes each fiber randomly lighter or darker. Hue Vary makes the color of each fiber shift slightly, so a red fiber might become orange or purple. Often you don't need to use large values for these settings, but small settings are often quite realistic.

Image Map Coloring

The Salt and Pepper controls give you a range of colored fibers and complex ways to mix them. Using S panels you can even make patterns like zebra stripes. But often you simply want to paint the color of the fibers directly. You can do this with the Color Image controls at the top left of the interface.

When you use a color image to set the fiber colors, the fibers become tinted by the image color. But Salt and Pepper coloring is still active which makes it very easy to realistically randomize the fur color. The image map color is just multiplied by the Salt and Pepper color. If you leave Salt and Pepper at full white, the fibers will use the color of the image map directly. It's common to use Salt of pure white and Pepper of a tinted light grey shade to cause some natural variation to the image map colors.

The Bright Vary and Hue Vary controls are also active, and further modify the fiber colors after they've had the image map applied to them.

The selection and options that control the image map are very simple, allowing you to pick the image, projection type (planar, cylindrical, or spherical), axis, and sizing options.

Clump Inheritance

The final control is a little different than the previous ones. When you're using clumping it's often useful to make the fibers in each clump a similar color, but have random variation between different clumps. At other times you may want the fibers inside the clump to vary too. Clump Inheritance allows you to choose between these modes. High values of Clump Inheritance will make every clump have its own coloration, with very little variation between the fibers in the clump. Low inheritance will make each fiber vary its color even within the same clump.

It may seem that there are too many methods for setting fiber colors, but after studying fur for so long, we're sure that they're all necessary to capture the true richness of real fur. Study a dog or a cat when you next see one, especially one with multicolored fur, and you'll learn a lot! Luckily, hair coloring is usually much much simpler than animal fur.

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