Hey there, I’m trying to use material generated gradient to mask a mesh particle. But whenever I spawn the particle the gradient seems to be world position oriented. I’m basically using this setup:
Not sure what I’m doing wrong
If you have the same graph than in the video you posted:
You are using the world position to create this gradient you are seeing. World position is a vector with a value for X, Y and Z, you can see it as 3 different gradient in each direction for your case. Then at the very end of the graph, there is a ComponentMask node that enable only the Blue channel that match the Z axis. That’s why you’ll always have a gradient going up in the world 
If you want the gradient to change when you rotate your object for example, maybe try to play with the object local position instead of it’s absolute world position. Or another way of doing it in world space would be to rotate the world space to orient the axis you want in another direction.
Hope it helps 