'Soft' Dot Product

Anybody know of an easy way to create the same fall-off on a surface that directional lights and things do? I’m trying to create a planet earth going around the sun, but rather than use a directional light I’m just going to use a world-space position of the sun and calculate the falloff on the surface from that.

Problem is, the Dot Product is giving me either a solid black or a solid white colour, even though I’m sure it shouldn’t be doing that. This is probably really simple and I’m overlooking something very basic. Any ideas? Just imagine two colours that blend into each other accross a sphere surface, that’s what I’m after. In it’s most basic form it’ll drive a lerp node between Night and Day-time maps on the Earth.

With the position of the sun available you would first calculate the light vector and then take the dot product of this vector and the surface normals.

Ahhh, the normalize step was what I was missing, that makes sense. Thanks chap :slight_smile: