9

518 Chapter 8: Modifiers
Tip:
To check the numerical order of splines, go
totheEditableSplinelevelofthemodifierstack
and access the Spline sub-object level. Then click
each spl ine in tur n and check its ID number at the
bottom of the Selection rollout. It also can help to
make sure that each spline’s first vertex is where
the hair roots should be.
Guide Ha irs
Storing and manipulating millions of dynamic,
simulated hairs is demanding on today’s
technology. Therefor e, just as standard 3D
graphics technology uses boundaries such as
surfaces to describe solid objects, Hair uses hair
“guides” to describe basic hair shape and behavior.
Guides (yellow) occur at each polygon corner.
Hairs (red) are interpolated between guides.
When the g rowth object is a surface, Hair And Fur
generatesguidehairsatthecornersofpolygons.
When the growth object is a spline, the spline
sub-objects are themselves the guides.
For surface-grown hair, you can manipulate
the guides with styling tools (page 1–526) to
form a “control volume” that gets populated by
interpolated hairs. The hairs can then be further
manipulated with distorting controls such as Kink
(page 1–542) and Frizz (page 1–540), w hich can be
driven by maps or solid textures.
Frizz settings affect the hairs but not the guides.
By default, a percentage of hairs are displayed
in the viewports, but surface-g rown guides do not
appear except when you are working at the Guides
sub-object level. You can adjust the viewport
display of guides and hairs with settings on the
Display rollout (page 1–549).
Guidesarealsousedtocalculatedynamics.After
this calculation, hair interpolation takes place
when you render. This is when parameters such
as Frizz, as well as displacement and coloration,
are calculated. You don’t have control of every
single hair, but this two-phase process ma kes the
creation of realistic hair computationally feasible
on a typical computer.
Styling Hair
TheHairAndFurmodifier’sgrowthsettings
haveagreateffectonthehair’sappearanceand
behav ior, but you can also manipulate the guides
directly (or in other words, style t he hair).
For surface-grown hair, use the tools on the Styling
rollout (page 1–526). First, select t he surface whose
hair you want to edit, and then on the Modify
panel, either click the Sty le Hair button on the
StylingrolloutorchoosetheGuidessub-object
level from the Selection rollout (page 1–521) or the
modifier stack d isplay.