I am experiencing an issue with colormaps applied to a 3D data set.
If I display the full data (a distance map) all works as expected: the intensity values (distances) a nicely colored. Then I set the last z-slice to zero. If I render this changed data set the colormap becomes binary: the whole area of the distance map gets the same (“maximal”) color.
If I zero the second-last slice instead of the last all is fine. All this is independent of the particular colormap chosen.
To demonstrate I include a test script and an image.
If you reduce the size of the image (commented code) all three cases render fine.
colormap_test.zip (1.1 MB)