Map Range makes it possible to place the nodes inside the group and adjust them at its discretion due to the presence of several input sockets. In this, its advantage compared to Color Ramp, but Color Ramp has B-Spline interpolation. I tried to connect mathematical nodes as shown in the screenshot. At the same time, it was possible to get a roughly similar image, but when the slider moves the texture group, the texture still behaves differently.enter image description here

Question: Is there a way to repeat the B-Spline interpolation using Map Range and manage it outside the group?

Thank you!

  • $\begingroup$ I've looked through several pages of math explanations for b-spline interpolation and found loads of complex functions incl. matrix formulas, but no simple "summary" yet. A workaround would be to use values as drivers for the sliders of a Color Ramp set to b-spline interpolation. Using those maybe in combination with a Mix RGB node you could "import" the settings through a group input. Example here in my answer: Color and position input for Color Ramp node $\endgroup$ Apr 11, 2022 at 9:23
  • $\begingroup$ You can put drivers on the stop-positions in a color-ramp, and drive them from the input fields on a containing group, but I haven't figured out a way to use 'self' or somesuch to copy the group for re-use with independent inputs.. it has to be rebuilt for each copy. $\endgroup$
    – Robin Betts
    Apr 11, 2022 at 10:30
  • 1
    $\begingroup$ @RobinBetts Yes, this is definitely not the best solution... but as long as nobody presents a formula (but I guess there is one) for the b-spline interpolation, I don't know a better way. $\endgroup$ Apr 11, 2022 at 10:35


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