Lesson in session

First of ,

##
What is smoothstep

Smoothstep is a,… well :

“Returns a smooth Hermite interpolation between 0 and 1, if *x* is in the range [ *min* , *max* ].”

This, according to microsoft.

Essentialy it takes your value and remaps it as if it lay between min and max instead of 0 and 1

To better visualise that, here’s a graph for smoothstep(.2,.4, (x=y)); (KINDA)

*black is x=y, red is the result of the smoothstep*
*Sidenote: This is an artist rendition of what happens,to help visualise it when making your shaders, in reality this function is a lot more squigely and smooth, therefore smoothstep.*

As you can see any value outside of .2 and .4 will become either 0 or 1.

Any value between .2 and .4 will smoothly interpolate between 0 and 1.

##
How to use

That is kinda up to you, but here’s how I use it:

Here, Curve will decide how far along the 0 to 1 value I animate the cutout, and

soft will decide how feathered my cutout is.

Here’s an example:

*This is my x uv’s on this plane, it’s a smooth gradient from 0 to 1*

*This is the curve animating from 0 to 1 and back*

*This is soft animating from 0 to 1*

*And this is how powerful the combination of the two is*

*And here is the same thing but with a noise texture instead*

Now just feed this result into your alpha channel and you are set.

PS_ Sorry for the long post.