6 modules - PI-VR GmbH

6.4 Rendering» Photon Tracing Notes and Tips Photon Tracing has its main advantages in interiorscenes. In exterior scenes most of the light illuminates the scene directly,the default full global illumination mode in VRED shows the best performancein this case.Be aware that the number of photons emitted doesn’t resemble the numberofphotons actually stored. If a photon misses the scene it will not be stored. Aphoton bouncing several times in a scene might be stored more than once.Tokeep the number of emitted photons as low as possible, place any light emittersin a way that most photons will hit the scene.When using Final Gathering scenes may suffer from light leaks if the photonradius is set too large. Light leaks mainly result from bad geometry in architecturalscene. An example would be an interior of a room illuminated througha window, the walls being modelled as simple planes. Any geometry near thewall would get light from outside the room since there is no actual thicknessof the wall. The solution would be to actually model the outer walls as well.Reducing the lookup radius may also fix the problem but may require shootingmore photons into the scene.Final gathering may also show problems in scenes with very strong indirectionswhere the scene is primarly illuminated by light resulting from reflectionsof a wall. In these situations disabling final gathering may give you a cleanerresult.» Display Output» Color:• Monitor Colorspace:· Simple Gamma· sRGB IEC 61966-21· A.RGB98203