I would like to create an object with a custom gradient in opacity.
I start with a curve (or more generally, a function of all three coordinates) that contains opacity values for the object I want to display. So for e.g. a cube extending from 0 to 1 in all three dimensions, that function would spit out the opacity value I want for each point in the cube. That way, I can model a cube with exponentially falling opacity or even an opacity that falls and rises again when going away from the center.
Does anyone have an idea how to achieve this? Thank you!