Why does GradientMap not let you use curves in the material editor?

[maasj]

Trying out gradient mapping and the GradientMap nodes only accept T2D inputs. But everything in the docs is about using curves and curve atlases for gradient mapping. This is frustrating I want to use the ‘index’ feature of the Gradient Map function but it will only accept a texture and not a curve. The whole point of curves is to be able to do it in engine? Anyone know how to do this?

[Hyperloop]

Here’s an example of how to do this with curve atlas, based on unreal’s documentation.