9

Cloth Modifier 583
Clo th Forces —
Add forces (that is, space warps in
thescene)suchaswindtothesimulation.Click
ClothForcestoopentheForcesdialog. Toadd
forces to the simulation, in the Forces In Scene
list on the left side, hig hlight the forces to add,
and then click the > button to move them to the
Forces In Simulation list, thus adding them to the
simulation. Thereafter, the forces affect all cloth
objects in the simulation.
To remove forces from the simulation, in the Forces
In Simulation list on the right side, high light the
forces to remove, and then click the < button to
move them to the Forces In Scene list.
Simulation group
To run a cloth simulation, click any of the
threeSimulatebuttonsinthisgroup. Tohalta
simulation, press
Esc or if the Cloth Simulation
dialog is open (i.e., Progress is on), click the Cancel
button.
Simulate Local—Starts the simulation process
without creating animation. U se this to drape
the clothes on a character or sew the panels of a
garment together.
Simu lat e Local (da mped)—Same as Simulate Local,
butwithalargeamountofdampingaddedto
the cloth. When sewing a garment together,
sometimes the panels come together at h igh speed,
causing problems. Using a damped simulation
alleviates this problem.
Simulate—Creates a simulation over the active
time segment. Un like Simulate Loc a l, this creates
animationdataintheformofasimulationcache
at every frame.
The simulator advances by a time step called
dT. The initial va lue is the Step setting on the
Simulation P arameters rollout. When the
simulator encounters certain situations, it
decreases dT in order to overcome the obstacles.
Sometime later, the simulator increases dT again
uptothemaximumStepvalueyouset.Thecurrent
valueofdTappearsontheClothSimulationdialog
that shows the progress of the simulation as it ta kes
place (see following).
WhenthesimulatordecreasesdT,itshows"dT
decreased" on the Cloth Simulation dialog along
withoneofthefollowingmessages(explanation
follows each message):
• could not solve equations – The solver could
not solve the equations of motion.
• cloth has become over-stretched – In
attempting to solve one step, some edges of the
cloth b ecame too elongated, indicating a failure
of the solver.
• cloth-solid collision velocity was too large –
The speed of the cloth relative to that of the
collision object is too high.
• cloth-cloth collision velocity was too large –
The speed of colliding cloth parts is too high.
Progres s—When on, opens the Cloth Simulat ion
dialog during the simulation. The dialog shows the
progress of the simulation, including information
about time, and messages about errors or time
step size adjustments.