Hi, I'm not sure if it's what you need, but here's a technique . First i've used a terrain for the mountains . I've exported the terrain grayscale image and edited it in Photoshop . I've done a posterize function to make the terrain heights more readable, added a layer and painted the river on it . Notice how it starts on the brightest shade and ends on the darkest one . I've deleted my terrain layer to have the river in black on a white background . Then, back in Carrara, i've edited the shader of the terrain : i've put a multi-channel mixer, with my mountain shader in one source, a water shader in the other and the river texture map as the blender . As i've used the "water : waves" function for the bump of the water, i'd be able to animate the flow of the river . Here it is, i hope this helps . litst