Diverging Log Lookup Table

This question is prompted from the MakeLUT function in the DisplacementPlot example:


The MakeLUT function shows how to generate LUT’s with diverging color schemes as described by Kenneth Moreland on his website (given on the example’s webpage).

Is there a way to create these diverging LUT’s using a vtkLogLookupTable?

I know that for scalars I could always take the log of the scalar and use a linear vtkLogLookupTable.


What are you getting? An error? Wrong colors or no rendering at all?



Hi Paulo,

I didn’t try it – yet. In looking at the code in MakeLUT, it didn’t appear that a log table would work.

I’m curious if anyone has diverging log tables working.



Well, give it a shot and see what happens. :slightly_smiling_face:



Will do. I should have tried it, but have been juggling too much – still am.


Well, I tweaked the displacement example that I mentioned before and the log LUT worked. At first there was the error:

vtkLookupTable.cxx:160 ERR| vtkLogLookupTable (0x1ee46f0): Bad table range for log scale: [-1, 1]

When I changed the range in the example, it worked and there was no error message. I need to check this on something more complex in the future. But, at least there is something.


The log function is undefied for negative arguments, thus the error.

Yes, I knew that. I just didn’t see that the example was setting a definite range.