DavidGraham
Veteran
I am assuming shadows for area lights are also ray traced hardware shadows?Triangle RT, "hardware"
I am assuming shadows for area lights are also ray traced hardware shadows?Triangle RT, "hardware"
I don't know of any categoric algorithmic errors (things are compared to the reference PT fairly frequently), but unfortunately there are still content details and approximations that can affect the output a lot. Specifically the quality of the BVH, but also sometimes managing the Lumen surface cache, particularly with complex meshes or lighting setups.It always seems like there's some sort of occlusion rejection error in UE5, as the reflections are hybrid screenspace/worldspace it makes sense that there could be errors even with RT all set up.
I presume there might be some talks at some point but seeing as it's all in the public source code/engine release, some high level points from my perspective **as of today** (this is all still very WIP, and will almost certainly change rapidly!):Regardless, great demo! Really cool to see, looking forward to details on how on earth this even works. Restir? Shadowmaps? Hybrid?
Correct. Per above the directional light is the only VSM in the demo, and it's only really visible as the soft moonlight and fog shafts.I am assuming shadows for area lights are also ray traced hardware shadows?
Awesome news! Previously Epic stated that they will streamline the shadow systems in the engine to just VSMs and RT, they said they will expand the use of ray traced shadows along side VSMs and mix and match between the two, I am so glad they kept true to their word and applied both techniques in a visually pleasing way.Raytraced shadows preferred (and used exclusively for the local lights in the demo), but can also be used for VSM SMRT projection, or a mix of both (selected per light, not a hybrid for a specific light). This is expected to be useful to folks who still need to use some VSM lights in cases where the RT geometry is not detailed enough. Ex. soft area lights use RT, sharp point/spot lights on detailed geometry possibly still using VSMs
For reflections there are currently 4 levels of doing them in UE5. You pick the one that suits your desired visual output/performance.there's some sort of occlusion rejection error in UE5, as the reflections are hybrid screenspace/worldspace it makes sense that there could be errors even with RT all set up
Hardware Raytracing
Release 5.5 has made many improvements to the underpinning systems which all fall into the external-facing hardware raytracing category (HWRT). These lower level systems all impact the performance and capabilities of Lumen, Path tracing, and Light Baking. There are improvements to asynchronous evaluation of raytracing code, improvements to caching and better management of acceleration structures. The intent of these changes is to make it feasible to utilize HWRT at higher refresh rates on platforms for which there is hardware support.
Yeah, that was the big reveal that had my jaw on the floor, I fully expected it to be running on a 4090, but on a PS5?megalights looks very cool.
UE 5.5 roadmap here. Haven't read through or watched the fest video yet.
@Dictator
That megalights demo is live on a ps5? Jesus.
That Mega Lights demo looked awesome. I can't see how any game on PS5 could ever look like that though.
Since Megalights are 'experiemental' in 5.5, it begs the question of how quickly the feature makes it into productions? Is it a feature that can just be turned on mid or towards the end of development? Those dictate the timeline for shipping games using the feature?
Thanks. That's great news and great work with MegaLight, the demo is really impressive (particularly when running on a PS5).Triangle RT, "hardware". In Lumen (and most RT implementations) screen space rays are still used together with triangle traces as well since the RT scene lacks detail in scenes of any significant complexity.
Took a quick look and it looks like probably the sweep in that one drone shot it at least partially because of some limitations in how many lights can currently affect the distant Lumen scene. In the future I imagine the goal is for this to be more stochastic as well, but currently the megalights sampling supports direct illumination/shadowing.
The many shadow-casting light sources look very good. A significant leap compared to before. In Robocop, the many missing shadows bothered me.
By the time next gen consoles arrive there should be UE6 announced.
FWIW there's nothing special with megalights and geometry support - it's just whatever is in your RT scene (if using RT). WPO support in RT is just disabled by default since it is extremely expensive.