Without caustics
With 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:
Caustic effects must be turned on in the Options dialog box.
One or more specular materials must be set to cast caustic photons.
One or more diffuse materials must be set to receive caustic photons.
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 Materials Illumination PropertyManager box for one or more specular materials.
Select Caustics Receive on the Illumination tab of the Material Editor dialog box for one or more diffuse materials.
Caustics Cast and Caustics Receive are unavailable if you select All materials cast and receive caustics by default on the Illumination tab of the Options dialog box. You cannot control the effects on individual materials.
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.