NVIDIA offers a vendor-specific extension:

https://www.khronos.org/registry/vulkan/specs/1.2-extensions...

I guess this will first be elevated to a vendor-neutral extension and (I guess) eventually will move into the core API.

One would have thought that they might have learned from what happened with OpenGL that this is a clusterfuck and leads to fragmentation...

Nah, https://vulkan.gpuinfo.org/listextensions.php

They learned from CUDA that this is indeed the way to own the whole market.

As flohofwoe has pointed out, yes this can currently be done using Nvidia specific extensions.

If you are interested, a friend of mine and a few coworkers pieced together a small proof-of-concept game engine in their spare time that uses Vulkan ray tracing on Nvidia RTX cards. They finally released it on GitHub a few days ago:

https://github.com/W4RH4WK/Raygun

I also submitted it on HN, but with little interest so far: https://news.ycombinator.com/item?id=22037474

There are days when I wish that DirectX was the open standard, rather than the other way around. It's such a cleaner, better designed API - quite possibly because it was not open, and so it doesn't have anywhere near as much of the design-by-committeeisms that infect OpenGL/Vulkan.

All other 3D APIs are like that, including game consoles.

OpenGL got lucky with Doom and Carmack's charisma, followed by Apple's decision to adopt it alongside NeXTSTEP.

Copland was going to use QuickDraw 3D.

Have a look at this: https://www.youtube.com/watch?v=xpxVAoXaVgg