Bring back scalar opacity unit distance in volume rendering
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
In the color map editor for ParaView 4.0 and earlier, there is an option called "Scale" that maps to the scalar opacity unit distance value in the VTK transfer function class.
Most of the time ParaView does a fine job automatically setting this value based on the diagonal of the data's bounding box. However, if the data is very thin, the unit distance could be set too large to see anything through the thin part of the data. There is no way to increase the opacity enough without adjusting the unit distance.
So although this parameter is rarely use, I think it should still exist in the GUI for those times when you need it. Obviously, this parameter should be hidden as an advanced option.