We do not use hardware raytracing on any platform.

For us it was important to still support regular meshes and that the morphs integrate well into a world full of Nanite objects. :)

Yes Dreams also used distance fields as well as they had similar constraints. Alex did a excellent talk at SIGGRAPH about it: advances.realtimerendering.com/s2015/mmalex...

In case you were wondering how these are rendered here is a visualization I spend way too much time on. :)
bsky.app/profile/p1xe...

Please note that the yellow'ish surface in the illustration doesn't really exist. All we know is the distance from the surface, so we march until we get to the "iso threshold".

This method is called "sphere tracing". It exploits the fact that we know for sure that there is no object in the sphere with radius d (distance to closest surface) at the current location. This decreases the necessary ray marching steps dramatically and makes it feasible to use implicit surfaces.

We called these "Lumen Virtual Lights". With MegaLights they probably won't see much use in future projects though. :)

That's correct. It works surprisingly well and didn't really degrade performance that much. :)

Absolutely!

I agree. This is mostly why I didn't stay in academia to come back to the industry. :)

I'm glad that my little visualization helped to illustrate how distance fields work. :)

I do want to stress though that the morphs in keeper do not use meshing or in other words when objects combine / blend / separate no new mesh is computed for rendering, mostly because it would be prohibitively slow for the resolution we need. I'll talk about how we render the morph surfaces soon.

You can see this nicely in this closeup. Notice how the number and orientation of the edges changes on the left side as both meshes are merged.

The topology of my madness is a infinitely regressing manifold! Haha.

For the implicit surface? This is done using the distance field gradient.

Hehe. Clay... the original implicit surface representation. :)

Of course implicit surfaces representations have other problem. I'll talk about these issues in the future.