Graphics Reference
In-Depth Information
Creating Clumping, Roughness, and Kink
When you've finished these steps, you'll have a reasonably convincing ball of hair you can start experimenting
with. You'll notice right off the bat that the hair you've made so far is much too perfect. No animal or human
hair is as unmussed and uniform as this. You can fix this by adjusting values in the Children tab.
A very useful parameter is the Clump value, which determines the degree to which the hairs cluster together
in bunches around the parent hairs. Natural hair almost always clumps slightly, so adding a small clumping
value often gives a more-realistic effect. A positive value makes the tips of the hairs meet, whereas a negative
clumping value causes the roots to be bunched to close together and the tips to spread. The Shape value for
clumpingisanalogoustotheshapevaluefortheparticlestrandsthemselves;apositivevaluecausestheclumps'
shape to be convex, bending outward, and a negative value causes the clumps' shape to be concave.
Roughness adds a random variation to the straightness of hair. The Rough1 value on the Children tab creates
a location-dependent roughness. This means that the kinks of each hair will be similar to the kinks of that hair's
neighbors. This is good for naturally kinky hair, as shown in
Figure 6-59
. Rough2 is random roughness, which
affects each hair individually. For this value, you can set a threshold so that the roughness affects only a per-
centageofthehairs.Thisroughnesscreatesamore-haphazard,disheveledlook.Thepurposeofthisroughvalue
is to add realism by giving a little bit of looseness to an otherwise well-put-together hairstyle. It should usually
beusedwithaverylowpercentagevalue.TheRoughEvalueaddsanunevencomponenttotheedgeofthehair,
with the Shape value affecting the shape of the resulting jagged edges of the hair.