The Rolling Operator can be used to simulate two dynamic
effects; the first is used to simulate a simple, natural rolling motion
for each particle. The second effect that can be created with this operator
is forcing a particle to stretch out by based on the speed it travels.
Natural rolling means that each particle's Edge Length is measured
and is used to control the individual rolling speed. Bigger objects will
roll slower than smaller ones.
ON - (Bool) This input data
stream determines whether the operator is considered 'on' or 'off'. You
can connect other operators to this input channel such as a Bool
Helper to activate/deactivate the whole operator.
Time - (Time) This input data stream is used to define the local
time for the operator when the user wants to override the default system
time.
Particle - (Particle) This input data stream reads in the currently
selected particle group that is to have its particles be affected by rolling
forces. The data stream MUST be connected and will be
highlighted yellow if it is not.
Type - (Integer) This input data stream takes an integer value
that represents the Rolling type that will control the particles' rotational
Primary Axis. Valid input values are 0 and 1, where:
Laziness - (Scalar) This
input data stream is used to override the Laziness spinner value.
Source - (Integer) This input data stream takes an integer value
that represents the Primary Axis for the rolling dynamics. Valid input
values are 0 through 2, where:
Invert - (Bool) This input
data stream is used to override the Invert checkbox state. Be aware that
this stream is only valid when the Type of rolling is set to Direction
of Travel.
Stretch - (Scalar) This input data stream is used to override
the Stretch spinner value. Be aware that this stream is only valid when
the Type of rolling is set to Direction of Travel.
Axis - (Direction) This input data stream is used to override
the Invert checkbox state. Be aware that this stream is only valid when
the Type of rolling is set to Rolling.
No Operator Outputs.
Rolling - When this option is chosen, you will be using a simple
rolling algorithm to determine the amount of roll imparted to the particles
you've selected.
Direction of Travel - Select this option when you want to have
the rotation controlled by the vector formed by the direction in which
each particle is moving. When selected, it will also activate both the
Primary Axis selection and the Stretch parameter.
Laziness - Values greater than zero will simulate an effect like
momentum of mass for each particle. The particles need some time to accelerate
until they roll at their maximum speed. A 0.0 value makes the particles
roll immediately after it receives a True condition.
P Axis - When Direction of Travel is selected, you are able to
select a Primary Axis for rolling. With P-Axis, you may set any local
particle rotation axis to be used for this effect.
Invert - As Albert Einstein noted some time ago: Everything is
relative. This includes the local axis of the particle. Use the Invert
button when you want to use the negative value of the selected P-Axis.
Stretch - When this spinner's value is greater than 0.0, the particles
will stretch along the movement vector dependant on their speed. Specifically,
the Stretch value specifies the percentage of their length per each unit
of the Speed setting. Therefore, if you set this to 2 while Speed is set
at 10, the particles are stretched 20 percent longer than their original
size along the axis of their travel. This spinner is only enabled when
Direction of Travel is chosen. Negative values are also allowed and this
will create a squeezing effect on the particles.
X / Y / Z Axis - Specifies
the rolling vector of the X, Y, and Z axes, respectively. These spinners
and the Variation spinner are only enabled when Rolling is chosen.