The Light Condition creates a True output whenever a particle
gets lit by a light source in the scene. Be aware that this operator tests
the illumination value for a particle (a single point in space) only.
If you need to get accurate surface illumination effects over an area,
you need to choose the MatterWaves
operator.
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.
Position - (Position) This input data stream is used to determine
the node or object that is used as the point at which the light illumination
is determined. If the selected object is not illuminated by the selected
light source (in the Light rollout), then the Output condition will be
false. Be aware that in order for this condition to function, you MUST
have a node selected and connected to this input port.
Normal - (Normal) This input data stream is used to calculate
the illumination of the particle based on its normal direction in relation
to the light source. In many cases, the normal is not needed since the
normal for a point (particle) is created by pointing directly at the light
source (full illumination).
Threshold - (Scalar) This input data stream is used to override
the Threshold spinner that determines the light intensity needed to generate
a true output condition.
Use Color - (Bool) This input data stream determines whether the
color value in the Light rollout (or piped in through the Color input
data stream) is used (Use Color = on), or if the default while color is
used (Use Color = off).
Color - (Color) This input data stream sets a color to be used
as a determining factor to see if it illuminates a particle. This color
value will only be used if the Use Color checkbox is active in the rollout
or if a true boolean value is piped into the Use Color input data stream.
Variation - (Scalar) This input data stream is used to override
the RGB Variation % spinner setting that determines the variation in light
color that illuminates a particle.
Output - (Bool) This output
data stream sends a true message if light illuminates a particle, and
a false message if light does not illuminate a particle.
Intensity - (Intensity) This output data stream sends the current
intensity value of the light source to other operators. If your light
source has an animated Intensity, then this value can be passed on.
Color - (Color) This output data stream sends the current color
value of the light source to other operators.
Direction - (Direction) This output data stream sends the direction
to the light source from the particle that generates a true condition.
REM. - Select any light from the list of lights in the dialog
above, then press the REM. button to remove it from the list.
PICK - Press the PICK button to activate the light selection mode.
From within the 3ds Max scene you can pick any light
type that should be taken into account by this condition.
Threshold - This parameter sets the illumination level at which
the operator should create a "True" output condition. If the
light intensity of a particle is higher than this value the output switches
to “true” (logical 1). Be aware that this spinner value can be animated
over time to make particles more or less light "sensitive".
Color checkbox - The Light condition is also able to react to
the light's color. Activate the Color checkbox and set any color value
you may want to use to control the output of this condition.
RGB Variation % - This parameter only becomes active when the
Color checkbox is turned on. In many situation, it would be exceptionally
hard to find the exact illumination color that will set the output condition
to "True", therefore this value lets you set a variation of
the color to react upon.