@jblackwell Since SER is mentioned, I have a surprise for you : SpaceJunkyard_NvRTX_Causitcs_5.2.rar - Google Drive
Press 1 to toggle between SW Lumen and HWRT, I got HWRT running faster on my 4090 coz SER significantly handling material sorting very well. If you have a very nice rig, you can try my CIty RT Over Drive mode which I added mesh caustics on those overwhelming amount of vehicles (don’t drive those cars ):City_NvRTX_Causitcs_521_Overdrive.rar - Google Drive
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I can’t wait to try this out! Thank you so much. My CPU is a 10th gen intel, so not very powerful, but my 4070 should probably do good work if I keep the resolution tame. This is truly spectacular, thank you.
I’m unsure if you were at all connected to this, but I was blown away by the RTX racer omniverse demo as well. The visuals were super impressive for the frame rate and all the interlocking systems, although I’m unsure if they ever released it for the public. Were you involved in that project at all perchance?
What’s the danger of driving the cars? Does the mesh caustics system lose substantial perf with dynamic objects?
No , I met a chaos physics issue when package old city demo from newer engine version like using version 5.2.1 to package city project from 5.1. When you tried to drive the car, physics is running crazy.
Ah, I see, thank you for letting me know, I’ll be sure to keep that in mind.
I tried out the space junkyard demo by the way, the integrator is incredibly effective even with the many thin emissive objects. It appears pressing 1 switches the renderer from your solution to what I presume to be a form of lumen, but I can’t find a menu that outlines much about the demo’s behavior. Is the integrator some form of RT overdrive?
@jblackwell It’s a very new feature just implemented in NvRTX Casutics branch. Thanks for High quality Restir GI, emissive materials cast dynamic shadows with NO additional cost, press 1 is toggling between HWRT and SW Lumen pipeline, basically, HWRT is faster than swLumen (no HW raytracing) thanks to SER which drastically improving material sorting performance. Also, DLSS 3 is included in that build. You can found that lag and ghosting issue caused by Restir GI as well as denoiser, we are working on DLSS 3.5 to eliminate that artifact. Additionally, we are working on OMM for alpha test foliage under HWRT scenario, which will bring a big leap to handle massive amount of foliage.
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Sounds good!
I also tested it, but GI was quite screen space, right? Maybe because it was SW Lumen by default but, when pressing key 1, it turns brutally noisy, specially noticeable at the final “room” of the groute, loosing a lot of details due to darkening massive areas. Is this as intended?
Thank you for your work!
@Miguel1900 It is not screen space like SSGI, off screen greenish emissive material can cast soft shadow like area lights with no additional cost, significantly accurate compared to SW or HW Lumen. We added SER support for Restir GI, even those small tiny emissive spheres can cast accurate off screen shadow.
@Miguel1900 The default pipeline is based on old RTGI which shot screen space rays, if you hit stat GPU you can notice the familiar pass introduced in UE4. Press 1 just turn off HWRT and HW Lumen, so SWLumen + VSM is the fallback.
We’ll definitely support it as soon as it is production ready from EPIC side 
Basically, every update from EPIC side like nanite and lumen got significant improvement since UE5.0.
The demo is just using high res Restir GI introduced in 2021 paper:https://research.nvidia.com/publication/2021-06_restir-gi-path-resampling-real-time-path-tracing plus some inline raytracing and SER optimization from driver side. The IQ and perf is pretty good on ADA (40)GPU. BTW, we also add reflection restir gi to compensate the missing GI on reflection, basically, character won’t be pitch black on reflection without direct lighting.
Oh great! So, this will be the sucesor of RTXGI, available again as a plugin for upcoming UE versions? (RTXGI was discontinued for UE5.1)
About the screen space commentary, I was thinking of it because of this effect, even when a little poertion of the scene is not visible because of a little object occlusion, like the pawn in the middle:
I see, I was very impressed by the overal quality and temporal coherence. I’m looking forward to testing the 5.2 caustics branch when I have the time to really do it justice, because the technologies on display are truly impressive.
I am curious, how well does NVRTX’s ReSTIR implementation support scattering events? In many of the demos and papers I’ve seen, I haven’t found too much information on how absorptive phenomena is handled in real-time.
I’ll add to that, I think @awsc you may want to have your exposure settings tuned, as the image would often crush to black in certain areas where it seemed inappropriate, making it hard to gauge the lighting quality.
For translucency absorption, it was already supported since version 4.25, for sss scattering still use raster screen space technique coz the real hwrt transmission is not cheap for realtime.
NO real manual light other than sun light and skylight is put in that scene, those small emissive objects are extremely difficult to handle efficiently and elegantly, they cast area light soft shadow on dynamic characters.
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The GI lag and denoiser ghost are the major issues we are currently working on as I mentioned above, hopefully, dlss3.5 can handle those scenario very well. If you limit the bounce count to 1, GI screen space update will be much faster, try those cavs r.raytracing.globalillumination.max bounce 1, r.screenpercentage 50,r.streamline.dlssenable 1(dlss3,you need to enable hardware acceleration in your windows graphics settings)
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That was what I was wondering. I know that multiple scattering events are usually pushing real-time PT further than it can practically go (with current algorithms), but I was also aware that the callisto protocol supported what it called ‘ray-traced transmission’ on fleshy entities, so I was curious if advancements had been made in the space. Although perhaps I should ask, how do you differentiate scattering and absolution?
By the way, for anyone interested: I just talked with SebHillaire on the Substrate feedback thread; he said that colored shadows (translucent surfaces casting translucent and colored shadows) is on the desired list of features for substrate, but there’s no timeline on when the technology will be ready. If any UE developer is considering making a game where colored shadows and caustics are a desired component of lighting, NVRTX is currently the only system that supports it, and their system is quite robust.
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