8

Hair Overview 505
order to m anipulate the guides directly (that is, to
style the hair), you wi l l need to launch the
Style
dialog (page 1–524)
. First, select the Hair and Fur
modifier you want to edit, and then click the Style
Hair button on the Tools rollout.
After styling guides, hair is interpolated between
neighboring guide pa irs.
To exit and accept changes, click the Done button.
To exit and reject changes, click the [X] button in
the upper right corner. When you exit, you are
returned to 3ds Max.
Mesh-based hair before and af ter styling in the Sty le d ialog.
With spline growth, you st yle the hair by editing
the growth splines in the 3ds Max viewports. Hair
always retains connection to the g rowth splines
through the Hair and Fur modifier.
You can style spline-based hair in t he viewports by
manipulating the splines.
Designating Collision Sur f aces
Hair’s guides have their own dynamics engine,
which is capable of collision. The engine supports
two different collision types: sphere and surface.
Surface collision simply b ounces hair off of
a polygonal mesh, spherical collision uses a
geometric bounding sphere of each element in
your mesh. For efficiency, each Hair and Fur
modifier contains its own set of collision surfaces
independent of those defined in other modifiers.
This means that if there is a collision object that
you want more than one Hair node to interact
w ith, you’ll need to add that as a collision object
for each of the Hair and Fur modifiers. To add
a collision surface to a Hair and Fur modifier ,
go to the modifier’s Dynamics rollout, choose a
collision method (Sphere or Po lygon), click the
Addbutton,andchoosefromthelist.Iftheobject
you wish to add is the one the modifier is attached
to, just tur n on Use Growth Object.
Light ing Consider a tion s
When rendering via the default buffer method,
Hair provides its own default lighting (an omni
light), unless you have one or more spot lights
in the scene. It ignores any other type of lights
present in the scene with regard to lighting the hair.
Ifanyspotlightsexistinthescene,bydefaultthey
areusedtolightthehair,andtheinternaldefault
omnilightisnotused.Thisisduetothefactthat
the
Hair and Fur render effect (page 3–216) “Use
all lights at render time” option is on by default.
Also, any spot lights set to cast shadow-mapp ed