How can I have a smooth transition between colors on a low poly model? I don't know what to call it but I have a low poly landscape right here, but my problem is its color.



I want it to have like some sort of gradient effect using different materials. If you don't understand, take a look at the islands in this picture.



It has a kind of gradienty thing with the islands. Basically the transformation of the color from green and brown on this color is seamless, and I don't want a sudden change of color in mine. I know it's impossible to make it follow my landscape with just one material, but I just wanna see if there's a simpler method like using random on object index or a color ramp, and I really don't wanna make this manually.
The gradient texture can do that. If you want to change the gradient orientation, go through a Mapping node first.