Both fur and hair form groups, bundles, tufts, or locks. (Four words which are synonyms.) Real hair and fur often "sticks" together in these kinds of clumps. When you get out of the shower, your hair is very clumpy, with large bunches of fibers glued together by water. After you dry your hair, you'll have fewer (if any) clumps, and the clumps you have left will be smaller and have fewer hairs. Sasquatch can make clumps like this for both fur and hair.
For fur, clumps are activated by the Clump Haircount control. This allows you to set the average number of fibers in each clump. When the control is at 0%, there are no fibers in each clump, so effectively you have no clumps, just individual fibers. As you increase Clump Haircount, you'll get more and more fibers in each clump, and the clumps will start to become more distinct.
Increasing Clump Haircount ( 10%, 40%, 70%, 100% )
The total number of fibers Sasquatch renders is not changed by clumps. If you have a surface with 500 clumps of 10 hairs each and you double the Clump Haircount, you'll get 250 clumps of 20 hairs each. So when you increase Clump Haircount, you'll get fewer clumps with more fibers in each.
The size of the clumps is controlled by Clump Size. This is independent of the fiber count; you can have a large clump which has only a few fibers in it, or vice-versa. When you have many many fibers in a very small clump (like when you have wet hair), all of the fibers will be packed together so tightly you probably won't even see the individual fibers.
Increasing Clump Size ( 10%, 30%, 50% )
Not all clumps have to have the exact same size. Clump Size Vary will randomize the size of the clumps. At 0%, all of the clumps will be the same size. At 100%, every clump becomes smaller by a random amount. (The maximum size of the clumps stays the same, but they're allowed to get smaller.) A setting of 50% will make clumps randomly sized from half to full sized. This variation is useful to make the clumps look less artificial.
A clump of fibers follows the same styling that a single fiber would, so you can use the normal fur tools like Frizz, Droop, and Curl. However, you can control how the individual fibers inside the clump behave. The most noticable clumping effect is when fibers "glue" themselves together at their tips.
Think about wet hair again. Each clump usually comes to a sharp point, not a wide, bushy, end like yarn or a rope. This effect is called Clump Matting. When you increase Clump Matting, the clump fibers will gather closer together at the end of the clump. A value of 50% will make the clump stay the same width everywhere, like a piece of yarn. A value of 100% makes all of the fibers merge into a point at the end of the clump. A 0% value will make the ends splay out and become bigger. This can make flower-like blooms, which are useful for landscape foliage.
Increasing Matting ( 0%, 30%, 60%, 90% )
The Clump Matting appearance can be further changed by the Matting Skew control. This determines how quickly the clump compresses. At 50%, the clump gradually becomes smaller along its whole length. A higher Skew value will make the compression happen mostly near its tip. A low value will make the bundle become small closer to the clump's base. Wet hair tends to use a small Skew value.
Increasing Matting Skew ( 0%, 25%, 50%, 75% )
All of the fibers inside of a clump are not perfectly straight; they wiggle around slightly. This can be controlled by Fiber Wiggle. Each fiber in the clump will be smooth and straight when Wiggle is 0%, but as Wiggle increases, each fiber will start to add some random variation to itself. The fibers are still restricted to converge at the tip due to matting, so Fiber Wiggle will sometimes make the center of the clump bulge a little bit. A small amount of Wiggle often looks realistic.
Increasing Fiber Wiggle ( 0%, 30%, 60%, 90% )
Finally, Fiber Length Vary makes some of the fibers in the clump shorter than the clump itself. This makes the end of the clump less dense than the beginning. When it's at 0%, all of the clump's fibers are the same length. At 100%, the fibers are random lengths ranging from 0 to the clump's length. Nearly all real hair and fur has some length variation in the clump fibers.
Increasing Length Vary ( 0%, 30%, 60%, 90% )
With hair, Clump Haircount isn't used. Instead you specifically define the number of clumps with the Clumps Per Lock control. This gives you exact control over the appearance of the clumps in your lock of hair. This is discussed in the hair chapter .