6 modules - PI-VR GmbH

4.14 Render Settings» Interactive/Still Frame Count: The two photon count values specify the numberof photons being sent into the scene for each image sample. Specifying a photoncount of 100.000 photons while having set the image samples set to 256 will resultin 25.600.000 photons send into the scene for a frame. More photons result insmoother results.» Lookup Radius: The lookup radius specifies the radius around a scenes’s hitpointused by the raytracer to find photons around the hitpoint. A larger radius allowsthe raytracer to find more photons but may result in slower lookup times.» Final Gather Quality: There are two ways to use the photon map. The firstapproach is always used for caustic photons. It gathers photons around a hitpointto calculate the incoming illumination. This approach gives very fast interactiveperformance and is capable to calculate all light pathes in a scene, but it mayrequire a very high photon count to get a clean image. The other approachis to use final gathering. In final gathering a one bounce indirect illumination isperformed before evaluating the Photon Maps. This is the default Photon Tracingapproach in VRED since it generates high quality images in a very short time.Setting the final gather quality to ”Off” enables the first approach while setting itto any other value uses the second approach.» Final Gather Radius: Sets the lookup radius used to find the nearest final gatherpoint during raytracing. Using a smaller radius will increase performance but itrequires more photons to avoid dark regions.» Final Gather Refresh: Setting the Final Gather Quality to 1 or higher, the updatefrequency of the Photon Map may be set. By default the Photon Maps are updatedfor each image sample, sending a large number of photons into the scene. Whilethis is necessary if final gather quality is set to ”Off”, it is often sufficient to updatethe Photon Map only once per frame and use it for each image sample to reducethe render times.• On Each Sample: This updates the Photon Map for each image sample. Thisis the default setting since it also works for scenes with animated objectsthat may cause flickering otherwise.• On Scene Change: The Photon Map is updated once per frame unless motion71