Caustics
Enables or disables the rendering of Caustics.
Specifies the caustics Mode to be used from the following options:
- Rebuild (don't save) - Redshift computes new caustic photons from scratch (for each frame) but does not save it to disk. Then the frame is rendered to completion.
- Rebuild (prepass only) - Redshift computes new caustic photons from scratch (for each frame) and saves it to the user-specified file. Final rendering is skipped.
- Rebuild - Redshift computes new caustic photons from scratch (for each frame) and saves it to the user-specified file. Then the frame is rendered to completion.
- Load - Redshift skips the caustic computation stage and the caustic data is loaded from the user-specified file in the parameter below. Then the frame is rendered to completion.
Light-emitted photons are independent from the camera settings, so fly-through animations can get away with generating the photon map once (on the first frame) and re-using it for all other frames.
However, if photon-emitting lights move or material settings are animated, a new photon map will have to be generated to account for these generations.
Specifies where to save or load the caustics data.
Max Photon Density[1..2147483647]
Specifies the maximum number of photons that can be stored in the "Blur Radius."
Higher values allow the photon shooting algorithm to store more photons per unit area which requires more memory but not necessarily improved image quality! Therefore we recommend leaving this setting at the default value of 200 because there is frequently little to be gained.
| Max Photon Density: 0 - 100 |
Controls the distance in world units around each pixel that is used to find photons.
Higher values result in smoother but blurrier results while lower values result in sharper but potentially more splotchy results.
This setting is closely tied to the maximum number of photons shot into the scene. As more photons are shot the Blur Radius can be reduced without resulting splotchy artifacts. If too few photons are shot the Blur Radius has to be increased in order to not be splotchy.
| Blur Radius: 0 - 1.5 |
When enabled, it allows Redshift to use a faster, pre-processed approximation that requires less searching for blurry effects.
Searching for photons during final rendering can be time-consuming and might slow down the render, "Fast Irradiance" allows caustics that are more blurry to render faster.
The preprocessing step happens after the photons have been computed and might take a few seconds but the savings when rendering are worth it, so it is recommended that you leave this option enabled.
Specifies the number of times a photon can bounce around the scene for reflections. A value of 0 disables all Reflection Caustics.
| Reflection Trace Depth: 0 - 10 |
Specifies the number of times a photon can bounce around the scene for refractions. A value of 0 disables all Refraction Caustics.
| Refraction Trace Depth: 0 - 10 |
Specifies the maximum number of times a photon can bounce around the scene for both reflections and refractions. This means that if the individual trace depth value for reflections or refractions is higher than the Combined Depth the resulting render will still be capped at the Combined Depth value.
| Combined Trace Depth: 0 - 10 |