Fancy a dip?
During my Masters course we had to create an underwater scene from an above ground reference. I wanted to expand on that and create an underwater scene from nothing. I have a lot of fluid simulation experience under my belt but I wanted to achieve the effect without using any actual fluids.
Geometry
I modelled the basic swimming pool shape then added two ladders and geometry for the vents and lights. The colour of the tiles is driven by the material shader. No textures were used making this project, it’s all procedural within Redshift. The barriers were a single piece of geometry modelled from reference and then copied along a line. This line had some animated noise added to each point to give the impression that the barriers were gently bobbing up and down in the water without having to simulate it.
Surface
The water surface is a detailed grid with noise applied to it to make it appear more like the surface of a fluid. I could have applied this at render time but I found that the scene was so light already it didn’t particularly affect render times having it at geometry level. Plus, you could dial in the effect visibly, in “real-time” this way.
Caustics and Volumetric
The main effect I used to make the underwater scene convincing was to generate a noise pattern in After Effects and use it as a mask in the Redshift light. As the noise evolves it is projected through the light onto the geometry below. By adding a volume contribution to the light you get the foggy shafts of light moving down from the surface, aka “God Rays”.
Fog
I had two options for adding to the distance / depth effect. One was to use Redshift’s built-in volume tools in the renderer to scatter a fog throughout the scene, the other was to generate a physical fog and place it in the pool. I went with the second option as I found I was able to dial it in a bit better and get a much more subtle effect. However, this option was slightly slower to render.
Rendering
The image below is the main beauty render straight out of Redshift.
And after a little colour grading in Premiere.
One final addition was to screen in some floating water particles provided by a stock footage site. I animated the position of the layer to make it match the camera movement and lightly colour graded it to match the scene.
As always, a tidy scene file, is a happy scene file!