gradient distribution from spline perimeter

[rivoli]

I have a floor with a herringbone pattern and tiles of four different colours from dark to light blue. I need to randomly distribute them, but with the dark ones along the clipping spline perimeter and fading to the light ones in the centre. I think I could handle it if it was a simple linear gradient going straight along one axis, but don't really know how to manage the distribution from the spline's borders.
I'm attaching a drawing to make things clearer.
thank you for any suggestion.
m

[Rokas]

Hi.
In this case it would be easiest to create a random noise map (3ds max gradient map can help)
And use that with RailClone Color map with mode "As Texture on Surface"
Attaching this file for closer inspection:

[rivoli]

Hi Rokas, that's actually quite clever. didin't even think about the colour map, I use it often with forest but never with railclone. I'll try it and see how it goes, reckon it can work out just fine.
thanks for the great support.
m