9

548 Chapter 8: Modifiers
aprecomputeddynamicssimulationwithHair:
(page 1–545).
Text field—Displays the path and file name for the
stat files.
... (ellipsis) button—Click to choose a name prefix
and location for stat files using the Save As d ialog.
Hair adds a four-digit frame number (with
leading zeroes) and the file name extension
“.stat” tothenameyouprovide(forexample,
hair_test0001.stat).
Delete all files—D eletes stat files from the target
directory.Thefilesmusthavethenameprefixyou
assigned using the ... button.
Tip: You can still use stat files even if you move
them to an other loc ation. Follow this procedure:
1. Open the MAX file used to generate the stat
files.
2. On the Modify panel > D ynamics rollout, click
the ... [ellipsis] button.
3. Use the Save As dialog to navigate to the
directory with the stat files, and then click any
stat file. Its name appears in the File Name field.
4. EdittheFileNamefieldtodeletethefour-digit
extension af ter the stat file name. For example,
ifthestatfilenameistest0033.stat,deletethe
“0033” so that it reads test.stat.
5. Click the Save button. The new stat file path
appearsintheStatFilesfield.
Now,whenyouplayorrendertheanimation,Hair
uses the stat files as originally generated.
Simulation group
Determines the extent of the simulation, and lets
you run it. These controls become available only
after you choose Precomputed mode and specify
stat files in the Stat Files group. Set Start and
Endtotheframesatwhichtobeginandendthe
simulation, and then click the Run button. The
software then computes the dynamics and saves
the stat files.
Start—The first f r ame to consider in calculating
the simulation.
End—The final frame to consider in ca lculating
the simulation.
Run—Click to run the simulation and generate the
stat files within the fr ame r ange indicated by Start
and E nd.
To abort a simulation while it’s running, click
Cancel on the status bar.
Dynamics Params group
Thesecontrolsspecifythebasicparametersforthe
dynamics simulation. The Stiffness, Root Hold,
and D ampen values can be mapped: click the
mapbuttontotherightofthespinnertoassign
a map . Grayscale values in the map multiply the
parameter’s value at that hair location.
Grav ity —Lets you specify a force that moves hair
ver t ically in world space. Negative values pull hair
upwhilepositivevaluespullitdown.Tocausehair
not to be affected by gravity, set the v alue to 0.0.
Default=1.0. Range=–999.0 to 999.0.
Stiffness—Controls the magnitude of the effect of
dynamics. If you set Stiffness to 1.0, the dynamics
will have no effect. Default=0.4. Range=0.0 to 1.0.
Root Hold—Comparable to stiffness, but affects t he
hair only at the roots. Default=1.0. Range=0.0 to
1.0.
Dampen—Dynamic hair carries velocity for ward
to the next f rame. Increasing dampening
increases the amount by which these velocities are
diminished. Thus, a higher Dampen value means
that hair dynamics w i ll be less active (the hair can
also start to get “floaty”). Default=0.0. Range=0.0
to 1.0.