I just saw, that the newest release of Paraview supports 2D Transfer functions for volume rendering which maps data with 2 components by applying the colormap to the first component to determine colour and the opacity function to the second colormap. However, my Impression ist, that it does not work.
Under “Scalar Coloring” I switched on “Multi Components Mapping” “Map Scalars” and “Interpolate Scalars Before Mapping”. Representation is switched to “Volume” of course.
Using a “Structured Points” data set as Input I can specify the two transfere functions independently (comp1 -> Color, comp2 -> opacity), but the opacity seems to have no affect (rendering is fast and the whole model is rendered as beeing opac).
When I use a structured grid as Input, the function for opacity and color seem to be Independent but the rendering looks like they are dependent. So the behavior is as if “Multi Components Mapping” is switched of.
Has somebody experience with this functionality and/or is there an example data set available that works?