For a description of Maya’s Volume
Light, see
Create > Lights > Volume Light.
- Type
-
- Color
-
- Intensity
-
- Illuminates by Default
-
- Emit Diffuse and Emit Specular
-
- Light shape
-
This determines the volumetric
shape of the light. Select a light shape from the drop-down list: Box, Sphere, Cylinder,
or Cone. Sphere is the
default.
Color range attributes
- colorRange
-
The
colorRange is the color of the light from the center to the edge
of the volume. By changing the values on the ramp (gradient) you
can decay or change color along the defined light direction. The
right side of the ramp represents the light color at the center
of the volume. The left side is the color at the outer boundary.
The effect of decay is accomplished by the interpolation (blend)
from the inner color to the outer color. The outermost color should
be black to avoid a hard boundary at the volume edge.
TipAdvanced ramp features
exist. For more information, see the following topics :
- Selected Position
-
Position of the active
color entry in the ramp.
- Selected Color
-
The color of the active
color entry.
Interpolation
Controls the way colors
blend in the ramp. Select an option from the drop-down list: None, Linear, Smooth, Spline.
The default is Linear.
- None
-
There is no interpolation;
the different colors show up as different bands in the final texture.
- Linear
-
The values are interpolated
linearly in RGB color space.
- Smooth
-
The values are interpolated
along a bell curve, so that each color on the ramp dominates the region
around it, then blends quickly to the next color.
- Spline
-
This takes into account
neighboring indices for a smoother effect.
- Volume Light Dir
-
The direction of the light within
the volume. Select an option from the drop-down list: Outward, Inward, Down
Axis. The default is Outward.
- Outward
-
Light moves away from
the center of a box or sphere and away from the central axis of
a cylinder or cone. It behaves like a point light.
- Inward
-
The light direction moves
towards the center of the light. This is a special effect that does
not simulate an area light, but is instead a simple change in direction
used for the light computation.
- Down Axis
-
The light direction is
down the central axis of the light. It behaves like a directional
light.
NoteShadowing does not
work properly for directions other than
Outward.
It always shadows as if from a point light.
Emit Specular has no
effect on Inward lights.
- Arc
-
Use
this option to create a partial sphere, cone, or cylinder light
shape by specifying a degree of rotation. Values can range from
0 to 360 degrees. The most common settings are 180 and 360, the
default. 180 is similar to slicing the light volume in half and
360 is the full light. This option does not apply to the box light shape.
- Cone End Radius
-
This
option applies to the cone light shape only. This is the relative
size of one end of the cone. At a value of 1.0 it is a cylinder,
while at 0 it is a cone.
- Emit Ambient
-
If
turned on, light affects surfaces in a multi-directional manner.
The default is off.
NoteEmit
Ambient may wash out shadows and look flat.
When combined with Emit
Diffuse, the lighting of a surface is 50% of the surface/light
angle, and 50% in a non-directional fashion. If Emit
Diffuse is off then the light is totally omnidirectional.
If Emit
Diffuse and Emit Specular are
off and Emit Ambient is on, the light behaves
like an ambient light with decay and a bounded range. This is quite useful
for adjusting lighting. It can be used with negative light intensity
to pull light out of defined regions.
Penumbra attributes
Penumbra
This
section applies to cone and cylinder light shapes only. This contains attributes
for managing the penumbra, the area of partial illumination around
the shadow border and the light. Using the graph you can adjust
the spread and the dropoff of the light. The left side of the graph
represents the intensity at the outer edge of the cone or cylinder
and the right side represents the intensity from the center of the
beam to the edge.
TipAdvanced ramp features
exist. For more information, see the following topics:
- Selected Position
-
This value affects the
active entry in the graph and is represented on the x-axis of the
graph.
- Selected Value
-
This value affects the
active entry in the graph and is represented on the y-axis of the
graph.
Interpolation
This controls the way
the values are calculated. Select an option from the drop-down list: None, Linear, Smooth,
Spline. The default is Linear.
- None
-
There is no interpolation;
the different values show up as different bands in the final result.
- Linear
-
The values are interpolated
linearly.
- Smooth
-
The values are interpolated
along a bell curve, so that each value on the ramp dominates the region
around it, then blends quickly to the next value.
- Spline
-
This takes into account
neighboring indices for a smoother effect.