Feature request: Add support for 2D transfer functions and editor in ParaView
VTK supports 2D transfer functions for volume visualization. 2D transfer functions allow a volume to be classified based on a combination of values. There are many articles in the literature that highlight the use of multi-dimensional transfer functions (e.g. http://www.cs.utah.edu/~jmk/vis01/node4.html).
tomviz already exposes a chart based 2D transfer function editor widget as shown here: https://blog.kitware.com/2d-transfer-function-support-in-gpuvolumemapper