September 24th, 2018

KELVIN WAVES:  The flip solver by default does not create proper wakes for moving objects. Objects will disturb the water creating a trail, but it will not create a self propagating wave. I researched some different options including using the ripple solver to create a displacement map, which could be added to the overall displacement. The other option I found was to use velocity pumps. With velocity pumps there is more control and it can be easily integrated with the existing network. Initially, I had to animate the pump geometry independently from the car, but soon created a rig that could be attached to any object, and reference the transforms so it moved with the object.

The velocity pump works similar to using it with the pyro solver. Create the geometry, convert to a fluid source volume and export to DOPs as a Source Volume. 

Initial velocity pump set up 

Kelvin wave V01

Kelvin wave V01 in motion

Kelvin Wave V02: from the reference I noticed that there were two kelvin waves coming from the front and sides of the car and another from the rear, so I created another pump to simulate this effect. 

Below is the double kelvin wave test applied to the overhead scene (shot 2) interacting with a set of incoming waves. The effect was pre-rolled enough to start with the wake already in place. 

Drifting test!

Shot 3: car exiting the ocean and interacting with breaking waves and shoreline.