6 modules - PI-VR GmbH

6.4 Rendering• Use Clamping: Sometimes sampling may result in single very bright pixelsthat are hard to antialiase. There are two options to get rid of these samples:· Tracing many more image samples: Casting more image samples wouldsample these bright pixels softer, but results in higher calculation times.· Clamping the image values to a specified maximum value. Be aware thatthe results may look dull if the clamping value is set too high.Caution: Activating clamping and reducing the value will reduce the maximumresulting image color range.» Pixel Filter: A pixel filter weights the image samples taken per pixel and thereforecontrols the antialiasing quality of the rendering. High image filter sizes may resultin blurry image results.• Filter: There are 10 different pixel filter available in VRED:· Box Filter: The box filter is the simplest pixel filter. It weights each imagesample equally. A size of 0.5 should be used for this pixel filter.· Triangle Filter: The triangle filter linearly distributes the samples betweenthe various pixels. It gives decent results and is therefore the default pixelfilter in VRED. It should be used with a size of 1.0 independent of screenresolution.· Gaussian Filter: The gaussian filter uses a gaussian function to weight thesamples. Samples near the center of a pixel receive a larger weight comparedto samples that are further away from the pixel center. It givesslightly better results compared to the triangle filter in some situations. Asize of 1.0 to 1.2 is recommended.· Mitchell Netravali: The mitchell netravali filter prevents blurring that mayoccur when using box, triangle, gaussian, or bspline filter by sharpeningthe image. It gives the highest quality result but may suffer from ringingon hard contrast edges. A size of 2.2 is recommended.· Lanczos Filter: The lanczos filter is a sinc-based filter that does an optimalreconstruction of the image. It delivers very sharp high quality results butmay suffer from ringing. A size of 2.5 is recommended.145