Shader Graph: Simple Math Nodes?

[birdcircus]

Hello!

Regading the “Wind” video of the Unity Shader Graph course:
I am a bit confused about a particular step: At ~3:50, we see the Voronai being multiplied by the Position, and then that result being added to the Position, and feeding that into the final Vertex Position…all good.

However, at ~5:27, when we change the graph to affect only the Y axis, we see the Voronai being added to the Y (or, G) of the Position, then all 3 axis recombined in a vector 3 and fed into the final Vertex Position (no multiply node this time)… I do not understand why in the first instance, we are using the Multiply node before the Add node, but in the second instance, we are only using the Add node? This is not acknowledged or explained in the video, and so Im not sure what the first Multiply node was doing… Thanks!

[Brian_Trotter]

Honestly, I think the multiply in this case was part of the problem, making the distortion look unrealistic. Using the multiplier in the 2nd case would actually eliminate the displacement we were shooting for. Remember that we started with a ProBuilder plane which was originally mapped on the X/Z axis. While we rotated that plane, we’re still doing our modifications to the Y position in object space, meaning that in this case, Y is actually 0 at all values along the plane. This means that if we multiply, then the resulting Y vector will always be zero. (This won’t always be the case, just in this case with the plane and it’s mapping along the X/Z axis. Putting this shader on a higher res sphere would have Y values all along the spectrum).

You could take the result of this addition and multiply it by a factor for increased displacement.