Hi vincent.hardy,
Thanks for exploring it, and yes, as mentioned, memory can go up (store a value for every point). I think it is always good to know some more options.
Did I get the same scene again? I checked, and nothing was hidden via layers or Takes.
Code and Python, thanks for keeping it out of the forum. Whenever something is posted with code, I will not hesitate to take care of it. Code is powerful, and that makes it dangerous. Thanks for understanding!
According to the manual's comment, "alpha" in MoGraph is slightly smaller with Fields, but I hope that has not affected anything else. Please explore what information could be used.
Since Colors can be created via Ramp based on gray values, it is easy to see that R, G, and B (interpreted as Linear) could be used as three independent information channels — one drive gray values (for a Ramp), the next the alpha information, and a third something else.
If you find yourself limited and have an idea, please always use the "Share Your Ideas" here:
https://www.maxon.net/en/support-center
My best wishes for your project