Usually, beauty pass is made in rendering software, but why not speed up entire shading workflow by moving it to compositing process? It’s pretty much typical standard in many studios nowadays, let’s take a look how to make that.
Here is the same fluid grid with different lights by areas. Every color represents another fill angle. In our situation green color is key light, red – fill light, blue – backlight.
What is cool, that in compositing every color can be separated as another pass. Three passes from just one rendering.
Below is a link to 3dsmax 2012 scene, Fusion and After Effects project.