Heya all, I’ve been trying to simulate the effect of rain drops flowing down the walls of a building, so far to little effect. This is the current setup:
http://i.imgur.com/zueWTl1.png
The idea is simple, take the rain colour, a gradient and the raindrop path, and set the gradient to pan down. Theoretically, the gradient should cause the rain to show over the texture and flow down. So far, it works, but the rain pathways are always visible in a noticeable dark colour and no amount of tinkering has been able to fix it. Does anyone know how I can achieve this effect without the pathways being visible? I’m thinking there must be a way to mask them out but I’m not sure. I’m pretty new to material editing so there’s every possibility that I’m approaching this the wrong way! This is the effect that I’m trying to create: Unreal Engine 4 - Raining Window Shader - YouTube
Thank you for reading 
EDIT: Resolved! Fixed it by multiplying the gradient with the rain paths and plugging that into the alpha, worked a charm!