Editing Rendering (computer graphics) (section)

=== Volumetric data ===
Scientific and engineering [[Visualization (graphics)|visualization]] often requires rendering [[voxel|volumetric data]] generated by 3D scans or [[Computer simulation|simulations]]. Perhaps the most common source of such data is medical [[CT scan|CT]] and [[Magnetic resonance imaging|MRI]] scans, which need to be rendered for diagnosis. Volumetric data can be extremely large, and requires [[OpenVDB|specialized data formats]] to store it efficiently, particularly if the volume is ''[[Sparse matrix|sparse]]'' (with empty regions that do not contain data).{{r|n=AkenineMöller2018|loc=14.3.1}}{{r|n=OpenVDBAbout}}{{r|n=Museth2013}}

Before rendering, [[level set]]s for volumetric data can be extracted and converted into a mesh of triangles, e.g. by using the [[marching cubes]] algorithm. Algorithms have also been developed that work directly with volumetric data, for example to render realistic depictions of the way light is scattered and absorbed by clouds and smoke, and this type of volumetric rendering is used extensively in visual effects for movies. When rendering lower-resolution volumetric data without interpolation, the individual cubes or "[[voxel]]s" may be visible, an effect sometimes used deliberately for game graphics.{{r|n=Bridson2015|loc=4.6}}{{r|n=AkenineMöller2018|loc=13.10, Ch. 14, 16.1}}