Depending on the Max version, there should be a MCG operator available
as simple modifier
Splines generate UV coordinates. If you want to have a gradient go along the length, apply a gradient ramp and set the W coordinate to 90. Also if you have 2018+ I believe, the new path deform can place UV's on the deformed geometry.Hope this helps!
You can copy uvs into a vertex colour channel using the channel info tool. This will give you gradients in both u and v directions with a couple of clicks