Hair and Particle Systems - Blender Master Class: A Hands-on Guide to Modeling, Sculpting, Materials, and Rendering - page 125

longest hair, and I blurred the weights more signifi-
cantly between areas to produce a smooth transition
in hair length.
When painting the length group, you can paint
outside the bounds of the hair-density group without
fear because hair will not grow outside the density
group. This allows you, for example, to grow long hair
right up to the edge of the density group, if you wish.

length and density to restrict the hair growth.
Then, I assigned the settings for the particles and
combed and cut the hair to make it look the way I
wanted. To make going through these stages easier,
I'll first discuss the main panels for particle systems
when creating hair-type particle systems. These are
discussed below in the order they appear in the
Particles tab of the Properties editor.

Particle System Properties
At the top of the Particles tab in the Properties edi-
tor, you'll find a panel showing the existing particle
systems assigned to the active object. Below this are
a few basic options that define what sort of particle
system you are creating:

Type (Hair/Emitter) Set this to Hair for creating
hair and fur. The Emitter type is for creating
dynamic, point-particle stems.

Advanced Turn this on for greater control over
particle emission.

Segments This determines how many control
points are used per strand of hair in order to
control the shape of the hair. More control
points mean you can incorporate more twists
and bends into your project. For short hair and
fur, the default value of 5 is fine, but for longer
haircuts, consider turning the value up.

Emission Panel
This panel controls how many particles are emitted
from your mesh and their distribution.

Figure 9-5: The hair-length vertex group

Adding a Particle System
Having added the basic hair vertex groups, I next
created a particle system to “grow” the hair. To do
so, I went to the Particles tab of the Properties editor
and added a new particle system using the + icon on
the right. (You can add additional particle systems
to the same object and switch between them using
the selector at the top of the Particles tab.)
Adding a new particle system brings up a
whole slew of panels, like the ones shown earlier
in Figure 9-1. I began modifying some of these.
First, I changed the particle system type from an
emitter of dynamic particles to a hair system by
changing the type setting to Hair. This change ini-
tially caused the mesh to look like a crazy hairball.
To turn the hair particle system into something
useful, I used the vertex groups I created for hair

Number Determines the number of particles the
particle system will generate. If you use child
particles in the settings, the total number of par-
ticles will be this setting multiplied by the num-
ber of child particles. Keep this in mind when
setting up a hair particle system because for the
same final number of particles, you could cre-
ate lots of parents and fewer children, or fewer
parents and more children. In general, you want
to have to edit as few strands as possible, while
maintaining control over the look of the hair
over the surface of the mesh. So when adding
hair to a simple head, Blender's default of 1,000
might be a little high, but for larger areas (for
example, when covering a whole creature in
fur), you might want to increase this value. For
the Bat Creature, I chose a value of 2,000.