Command entry: Create panel
(Lights)
Create a light.
General Parameters rollout
Shadows group
Shadow type
Advanced Ray-traced Shadows
Command entry:Select a light.
Modify panel
General Parameters rollout
Shadows group
Shadow type
Advanced Ray-traced Shadows
Advanced Ray-traced shadows are similar to ray-traced shadows; however, they give you more control over shadow behavior. Additional controls are available in the Optimizations rollout.
The mental ray renderer does not support Advanced Ray-Traced shadows. When it encounters a light with this shadow type, it generates ray-traced shadows
instead, and displays a warning to that effect.
Interface
Basic Options group
- Mode
-
Selects the type of raytracing for generating shadows:
- Casts a single ray of light toward the surface. No antialiasing is performed.
- Casts a bundle of rays. The same number of rays is cast from each illuminated surface. The number of rays is set using the
Shadow Integrity spinner.
- (The default.) Casts two bundles of rays. The first batch of rays determines if the point in question is fully illuminated,
shadowed, or in the penumbra (soft area) of the shadow. If the point is in the penumbra, a secondary batch of rays is cast
to further refine the edge. The number of initial rays is specified using the Shadow Integrity spinner. The number of secondary
rays is specified using the Shadow Quality spinner.
- 2 Sided Shadows
-
When on, backfaces are not ignored when calculating shadows. Objects seen from the inside are not lit by lights from the outside.
This costs a bit more render time. When off, backfaces are ignored. Rendering is quicker, but outside lights illuminate object
interiors. Default=off.
Antialiasing Options group
- Shadow Integrity
-
The number of rays cast from an illuminated surface. This is disabled when the raytracing mode is Simple.
- Shadow Quality
-
The number of secondary rays cast from an illuminated surface. This is disabled when the raytracing mode is Simple or 1-Pass
Antialias.
- Shadow Spread
-
The radius, in pixels, to blur the antialiased edge. This is disabled when the raytracing mode is Simple.
NoteAs this value increases, so does the quality of the blur. However, increasing this value also increases the likelihood of
missing small objects. To avoid this problem, increase the value of Pass 1 Quality.
- Shadow Bias
-
Shadow bias is the minimum distance from the point being shaded that an object must be to cast a shadow. This prevents blurred shadows
from affecting surfaces they shouldn't.
NoteAs you increase the blur value, you should also increase the bias.
- Jitter Amount
-
Adds randomness to the ray positions. The rays are initially in a very regular pattern, which can show up in the blurry part
of the shadow as regular artifacts. Jittering will convert these artifacts to noise, which is generally less noticeable to
the eye. Recommended values are 0.25 to 1.0. However, very blurry shadows will require more jitter. This is disabled when
the raytracing mode is Simple.