On – Turns rendering of caustics on and off . Multiplier – Controls the strength of the caustics. It is global and applies to all light sources that generate caustics. If you want different multipliers for the different light sources, use local light settings. Note: This multiplier is cumulative with the multipliers in the local light settings. Changing multipliers, while useful for artistic purposes, will result in physically-inaccurate scenes. Search distance units – Determines in what units the Search distance parameter is specified - World units or Pixels. The Progressive mode works only with Pixels. Search distance (World)/(Pixels) – Radius of search area circle. The Progressive mode works only in Pixels. The value set initially is automatically reduced by the solver during successive passes by up to a fourth of the initial value. For example, with the default value of 4, the search radius after being reduced becomes 1 pixel, allowing for detail to be resolved with that accuracy. If the initial radius is set to 16, the final radius is 4 pixels making the caustics look blurrier. As of V-Ray 5 update 1, it is recommended to leave the radius at its default value of 4. For the New map mode, when V-Ray needs to render the caustics effect at a given surface point, it searches for a number photons on that surface in the area surrounding the shaded point (search area). The search area is a circle with its center at the original photon and a radius equal to the value. Smaller values produce sharper, but perhaps noisier caustics; larger values produce smoother but blurrier caustics. For more information, see The Search Distance Parameter example or The Light Caustics Subdivs Parameter example below. Max photons – Maximum number of photons within the search area circle that will be considered when rendering the caustics effect on a surface. Smaller values cause less photons to be used and the caustics will be sharper, but perhaps noisier. Larger values produce smoother but blurrier caustics. The special value of 0 means that V-Ray will use all the photons that it can find inside the search area. See the Max Photon Example below for more information. Max density – This parameter allows you to limit the resolution (and thus the memory) of the caustics photon map. Whenever V-Ray needs to store a new photon in the caustics photon map, it will first look if there are any other photons within a distance specified by Max density. If there is already a suitable photon in the map, V-Ray will just add the energy of the new photon to the one in the map. Otherwise, V-Ray will store the new photon in the photon map. Using this options allows you to shoot many photons (and thus get smoother results) while keeping the size of the caustics photon map manageable. |