First, here's the functional result working in my test scene.
I built an Unreal material that displaced UV coordinates and perturbed a procedural radial gradient to get rays. This video is me walking through the system used to animate these rays. UMG animation is all Material Params.
Towerborne shipped early access with Coherent UI being used for their UI. The developer wanted to figure out how to work with the CSS / Unreal material interface workflow for UI VFX. So I worked with the UI team to establish a test scene where I could explore the connection between Unreal and the Coherent UI system.
We used the end of mission victory screen as a basis for our investigation. The visual target for this screen had a specific effect based off the Light Burst filter in After Effects. I thought this was a good effect to reverse engineer for this system because it would require several parameters that needed to be animated and controlled via CSS/Coherent.
One of the major challenges with the existing pipeline was that you needed UI artists/animators who had expertise in CSS as well as Unreal Materials and such. My system strived to create a pocket where an Unreal artist could iterate on the visuals without having to be trained in the specialized Coherent UI pipeline. I achieved this by keeping the CSS animation scripts simple 0-1, start-end values that would drive a lookup on a Curve Atlas. This way, artists could tweak parameter animation with these curves instead of writing raw values in the CSS keyframes.