The main goal for this material is to achieve the iridescent, multi-colored swirl pattern that is so often visible in soap bubbles. The bubbles can have many different looks: some patterns are very intense and colorful, while some are less so. In this tutorial, we are trying to achieve something in the middle.
The basic material is very similar to water, with the Refraction IOR changed to 1.01. This is a little cheat that makes sure we can see right through the bubbles, without any distortion. With thin-walled geometry, it’s easy to get artefacts if your geometry is not perfect, so this cheat will come in handy.
For Reflections, create a tileable swirl map in two different color variations.
To get the colors to change with the viewing angle, use a Mix map in the Reflection slot, with a Falloff map to drive the Mix.
The goal is to make the edges more red, while the center is more green and blue. To avoid the transition looking artificially smooth and perfect, use some noise in the Falloff map slots to break up the gradient.
