9

General Parameters Rollout (Hair and Fur) 535
actual number of rendered hairs as well, although
the apparent density, or fill, seems about the same
because of the additional transparency. Render
time a lso increases linearly.
Top: Hair Passes=1
Bottom: Hair Passes=4
Note: For best results when using the “mr prim”
hair rendering method (see Hair and Fur Render
Effect (page 3–220))withthementalrayrenderer,
be sure to set the Trace Depth > Max. Depth
value (see Rendering Algorithms Rollout (mental
ray Renderer) (page 3–116)) h igher than the Hair
Passes v alue.
Density —Thenumericvaluesetstheoverallhair
density;thatis,itactsasapercentagemultiplierof
the Hair Count value. Default=100.0. Range=0.0
to 100.0.
Thisattributeisalsomappableviathemapbutton
to the right of the spinner. Mapping lets you add a
texture map to control the amount of hair . An area
ofthemapwhosegrayvalueis50%willreduce
the a mount of hair grown in that area by 50%. To
change the overall hair count, use the Hair Count
value (see above).
Top: Density=100.0 + map
Bottom: The bitmap used to control density
Tip: Foroptimalefficiency,usetheHairCount
value to set t he actual number of hairs, leave
Densit y at 100.0, and use mapping to create
uneven hair distribution. Simply lowering the
Density value w ithout specifying a map causes
hairs to be created and then discarded, which
unnecessarily increases rendering time.
Scale—Sets the overall scaling for the hairs.
Default=100.0. Range=0.0 to 100.0.
At the default value of 100.0, the hairs are full size.
Reduce this value to make the hairs smaller. To
make the hairs larger, use the styling tools (page
1–526). Default=100.0. Range=0.0 to 100.0.
This attribute is also mappable via the map button
to the right of the spinner. Mapping allows you
to add a texture map to control the length of the
hair. An area of the map whose gray value is 50%
w ill cut the hair grown in that area to 50% of its
original length, with no shape change.
Scale value ramped from 0.0 (left) to 100.0 (right) using a linear
gradient map