Caustics
Caustic effects are the result of indirect illumination. Light is emitted
from a light source, goes through one or more specular reflections or
transmissions, hits a diffuse object, and reflects to the viewer. You
can enable caustic effects independent of indirect illumination effects.
For example, consider light patterns on the bottom of a swimming pool.
Light is emitted from a light source, the sun. The light goes through
one or more specular transmissions as it passes through the water. The
light hits a diffuse object, the bottom of the pool. Finally, the viewer
sees the caustic effects on the bottom of the pool.
For caustic effects to appear:
Enable caustic
must be selected on the Illumination
tab in the Options dialog box.
Clear All appearances
cast and receive caustics by default on the Illumination
tab to control Caustics Cast and Caustics Receive for each appearance.
If selected, you cannot control the effects on individual appearances.
A light source must emit caustic photons. Directional,
point, and spot lights can emit caustic photons.
To render an image with caustic effects:
Select Enable
caustic on the Illumination
tab of the Options dialog box.
Select Caustics
Cast on the Illumination
tab of the Appearances
PropertyManager for one or more specular appearances.
Select Caustics
Receive on the Illumination
tab of the Appearance
PropertyManager for one or more diffuse appearances.
Enable a directional, point, or spot light to
emit caustic photons. On the PhotoWorks properties PropertyManager for
a light:
Set Energy
to determine the total amount of radiated energy from the light.
Set C photons
to adjust the number of photons emitted by the light. Higher values produce
better results but images take longer to render.
Render the image.
Consider a brass ring on a table top. The brass ring is set to cast
photons and the table top is set to receive photons. A spot light illuminates
the scene and casts C photons. Notice the dots on the image rendered with
caustics. The dots are the photons cast by the spot light, then reflected
off the specular brass ring and displayed on the diffuse table top.
|
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Without caustics |
With caustics |
For more realistic images, increase the number
of photons so the photons blend together into a smooth pattern rather
than multiple dots with distinctive edges.
Back to Illumination
Options.