How would I do that? Advice would be helpful, thanks
What do you mean by "rivers"? Heh, that sounds funny, but what I am trying to gauge is if you mean just water inbetween two hills, or a huge water system that is made with pretty good percision...
There is a river-carving-function for heightfields - it sounds interesting if anybody has an idea for fractalterrains, too. My brain is working already ,-)
You could use a complex system of manually placed lakes, but that could take a long time to get right.
thanks for the inputs. At Ashundar, i found a similiar topic. You just create a default shader, attach it to the water shader of the lake, then put an image map shader (with an image mask) into the Opacity input of the default shader (Thanks Oshyan!!)