The original thread was introduced to discuss HDRP’s Experimental DXR project released back in 2019. Since the test project no longer exists, HDRP Ray Tracing is no longer in experimental, the discussion slowly drifted off into a general HDRP Ray Tracing discussion. A great place where we could learn and discuss, but it could also cause confusion for new people.
On a sidenote, the HDRP Ray Tracing subforum is still located under “Graphics Experimental Previews”. Since Ray Tracing has now left experimental, maybe a moderator can move the entire subforum to HDRP? Thanks!
This thread is a place to discuss
Sampling/denoising
Optimizations
Tricks
Showcase
Other implementations (how are they doing things, what is their performance like, what tricks do they use, what can we learn?)
To kick things off, I am personally working on a HDRP real time path tracing implementation for my game called Hyper Project. I’ve spent about a year studying various topics, making proof of concepts and writing a lot of notes and have now started on the implementation. I am ray tracing the full specular and diffuse path with 2-3 bounces and hope to bring this to VR.
Here I start something new in my pipeline: Manual Tone Mapping - yes I stopped to use ACES.
First of all, I compare always quality to the Corona Render Engine as the best render engine (this is the CPU field so is a slow time render but not that like Maxwell or Blender, and is similar to V-ray speed)
Corona has many advantages like very fast Photon Mapping+QMC system render (same I have also in KrayTracing in Lightwave), the best ever shader system/Nodes (I cover practically all in Unity), and a super Tone Mapping system (this gives big boost quality in Corona).
The tone Mapping system in Unity is also very good.
Here is a trick on how to avoid GI “Raytracing Effect” (poor GI bounce light).
Create Area Light DXR with a distance from the ceiling max 5 mm (so almost with the same level) and a size a bit bigger than the ceiling. The direction of light points to the ceiling.
Finished my 2-week dive in Cyberpunk 2077 with path tracing - got a lot (700+) of screenshots with inspiring lighting & detail level. If somebody don’t have time/don’t like gameplay - maybe those screenshots will be worthy - you can browse them on-line (to download all at once click on folder name there and pick appropriate option from drop down list): https://drive.google.com/drive/folders/1unqCfilu25MAp1P5ChwnSKrgFJagsmGD
Path tracing implementation is far from perfect but in general it’s working (and of course fog is not lit by GI and can ruin a lot of visuals when dust storm coming at day time). Anyway, amount of details in this game is impressive, monumental effort of the large game studio.
Yes, I installed it only for Path Tracing effect (The game is boring as hell itself…I do not even have plans to play it) On my hardware I got like 60 fps in 4K with maximum settings…pretty impressive performance!
I use this game only to walk in the night city and enjoy real-time GI/reflections and details.
Visible ghosting effect - somebody will complain - but this is real-time GI/reflection!
Next few years this will be standard in games because it is much easier to do it (no need fake solutions every 5 meters, optimization, baked maps, hundreds of reflection probes, etc)
I like in-game when moving objects have contact shadows, real area light shadows, raytracing reflections, and good contrast.
