8

Flex Modifier 687
Strength—
Sets the overal l spring strength of the
chase springs.
A value of 100 is rigid. Range=0 to 100; Default=3.
Sway—Sets the time for the object to come to rest
for chase springs.
Lowervaluesincreasethetimefortheobjectto
come to rest. Range=0 to 100; Default=7.
Use Chase S pri ngs—When on, enables chase
springs,whichforcetheobjecttoreturntoits
original shape. When off, no chase springs are
used, and the amount by which vertices move
depends only on their weights. Default=on.
Typically, for soft-body simulations when you
want objects to be influenced by forces and
deflectors, you would turn off Use Chase Springs.
Use Weights—When on, Flex recognizes the
different weights assigned to an object’s vertices,
apply ing different amounts of flexing accordingly.
When off, the flex effect applies itself to the object
as a monolithic whole. Default=on.
Typically, for soft-body simulations when you
want objects to be influenced by forces and
deflectors, you would turn off Use Weights.
Solver Type—Choose a solver for the simulation
from the drop-down list. The three choices are
Euler , Midpoint, and Runge-K utta4. Midpoint
and R unge-K utta4 require successively more
computationthanEuler,butaremorestableand
accurate. Default=Euler.
Tip: In most cases, you can use Euler successfully,
but if unexpected object deformations occur
during a simulation, try using one of the more
accurate solver types. Specifically, you might need
to use Midpoint or Runge-Kutta4 with higher
Stretch and Stiffness settings.
Samples—The number of times per frame the Flex
simulation is run at equal time inter vals. The
more samples you ta ke, the more accurate and
stable the simulation. When using the Midpoint or
Runge-Kutta4 solver, you mig ht not need as many
samplesaswithEuler.Default=5.
Tip: If your simulation produces unexpected
results, such as object vertices moving to seemingly
random locations, try increasing the Samples
setting.
Simple Sof t Bodies rollout
Lets the software determine spring settings for the
entire object automatically. Alternat ively, you can
use the
Advanced Springs (page 1–691) rollout
settings to specify spring settings between each
pair of vertices.
Create Simple Soft Body—Generates spring settings
for the object based on the Stretch and Stiffness
settings.
Note: AfteryouuseCreateSimpleSoftBody,
you can change the Stretch and St iffness settings
without having to click the button again; the
changes take effect immediately.
Stretch—Determines how much object edges
can elongate. When Advanced Springs rollout >
Enable Advanced Springs is off, the Stretch sett ing
is linked to the Advanced Sp rings rollout > Stretch
Str. and Stretch Sway settings.
Stiffness—Determines how ri gid the object
is. When Advanced Springs rollout > Enable
AdvancedSpringsisoff,theStretchsettingis