Learning Forum

[JamesWright]

tl;dr:

Rainbow colormaps are bad. I created two GitHub Repositories for better color map choices, courtesy of Kenneth Moreland. They are fluent_colormaps and cfdpost_colormaps for Fluent and CFD Post, respectively.

If any ANSYS reps see this, it'd be super nice if these could be officially implemented into new ANSYS versions!

If you have any questions or comments, please let me know!

Why not just use Rainbow like everyone else?

Generally, Rainbow is used as the color map for visualization, even though it has been proved to be quite poor for data visualization on a number of different levels. Information on this can be seen on Kenneth Moreland's website. 

Here's an example of a SBES (hybird RANS-LES) simulation result at a single time step. The domain is axisymmetric with flow going right to left:

It can easily be seen that the brighter blue is drowning out the smaller scale turbulence. The use of a better color map can improve this dramatically:

There are dozens of other color map choices that are an improvement on the standard rainbow. I've compiled a imgur album of examples so that you can easily see the different options.

 

[Rob]

Nice images. You do know that you can change the colour map in Fluent? 

[JamesWright]

Yes, but it's fairly tedious to do it manually. The GitHub repo has a function that can load and unload color maps without having to type it out one color space at a time.

[Rob]

Not really, you just change the scale setting. I'll flag the thread to DEV as it's a good idea. 

[JamesWright]

To be clear, I'm talking about the process of entering in new values to make a custom color map. Changing the color scale to one that's already in the system is quite simple. But a custom one would require that you enter in each 3 number color point on the scale one-by-one.

[Keyur Kanade]

I think this is available in ANSYS EnSight. But unfortunately EnSight is not available in student version. 

[JamesWright]

I think this is available in ANSYS EnSight

Think what is available in EnSight? I'm running an research academic license, so I might have access to EnSight.

[Amine Ben Hadj Ali]

Nice post!

[Karthik Remella]

Hello,

This is nice suggestion.

Regarding Keyur's comment on ANSYS EnSight and about available color maps, please have a look at the following post. It explains how to get to changing the color palette on EnSight. Please note that ANSYS EnSight is not available for the student version.

/forum/forums/topic/ensight-hot-iron-palette-from-an-image/

Thanks again for your inputs.

Best Regards,

Karthik

[Rob]

You can also use a journal to create the scales: not necessarily trivial but I don't know how much effort you put into the other images.  

As an aside, the feature is on the "to consider" list for Fluent next year: thanks for the suggestion. 

[JamesWright]

Once I found the script for adding the colormaps, I simply made a quick Python script to turn the csv's on Kenneth Moreland's website into the correct file format, so it didn't take very long. Also makes it much easier to add new colormaps in the future if they come about.

 

That's great to hear! I'd love to keep up with the ideas progress if that's possible!

[Rob]

As a user the only way will be to read the release notes: they're about the first entry in the list in the documentation.  Unless we're testing internally we may only find out about a feature a few weeks before release during out update training. 

Alternatively, keep watching the careers page, apply & get through the process and maybe get access to the pre-release software! 

[JamesWright]

Alternatively, keep watching the careers page, apply & get through the process and maybe get access to the pre-release software!

I'll keep that in mind! It'll be a few years before I finish up with school (doctorate), but I'll definitely be looking here when the times comes.

[Sam Mallinson]

Are there efforts afoot to permit import of .xml (say) so that you can use Fabio Crameri's extensive list of colormaps? As reported in Nature Communications article "The misuse of colour in science communication", https://www.nature.com/articles/s41467-020-19160-7

From the website for his article, https://www.fabiocrameri.ch/colourmaps/, he indicates:

"The colour gradients are perceptually uniform and ordered to represent data both fairly – without visual distortion – and intuitively

The colour combinations are readable both by colour-vision deficient and colour-blind people, and even when printed in black&white

The colour maps and their diagnostics are permanently archived and versioned to enable upgrades and acknowledge developers and contributors."

See also https://zenodo.org/records/8409685 from which you can download all of the suggested colourmaps in a single .zip file.

I use these colourmaps extensively with Paraview, an open-source CAE tool. It would be good if I could use them in ANSYS, a commercial CAE tool.

[Rob]

I suspect not, but keep an eye on the release notes as we are upgrading Fluent's colourmaps over time.