Like the title says, does UE4 have real time dynamic global illumination? I am not an expert in the engine so I dont know if UE4 has something like Enlighten or CryEngines SVOGI built in. There is that one from NVIDIA which only runs on high end GeForce GPUs and I read that there is something called LPV but is not developed further anymore, I dont know exactly.
Then there are options like DFGI, DFAO, HFGI etc. Are these still experimental / not work properly? So many options but somehow still missing what Unity (Enlighten) and CryEngine (SVOGI) have since years. I dont get it, why does Epic Games not give dynamic global illumination more love?
Can someone list the most common lighting methods to use in UE4? Lightmass with direct sunlight for shadows on movable objects? …
I know that Enlighten is also available for UE4. But its more or less exclusive for AAA titles which have the budget to buy Enlighten.
I feel like Epic Games made some kind of deal with Geometrics and NVIDIA to not create a real time dynamic global illumination solution or see it as like “hey, there are options for dynamic GI, look here and here”. Yes, Enlighten and VXGI are options. But like I said, Enlighten will cost likely six figures and VXGI not only runs exclusively on GeForce 900 and 1000 series but the performance is just horrible.
VXGI runs on everything, it’s not exclusive to Nvidia cards, it just requires a pretty beefy system.
As far as Enlighten is concerned, it kind of sucks, the lighting is actually precomputed, so you have all the same issues as baked lighting, it doesn’t work with dynamic objects or any objects that don’t exist at the time of building, so the only advantage is that you can move lights around
I didnt know VXGI also ran on AMD and lower than 900 series cards, nice to know. But like you said it will require beefy hardware so in that regard only a 780 Ti / Titan (Maxwell) would be somewhat suitable for VXGI.
I thought Enlighten is a real time dynamic global illumination solution? I knew that it was also precomputed but I heard that it doesnt take that much time compared to Lightmass and that Enlighten is considered as dynamic lighting.
SVOGI looks like to be the winner here then I guess? It not only looks good but performance is not as bad as VXGI. Some CryEngine games have SVOGI like the recent Kingdom Come: Deliverance and still in early access Miscreated. Seems to be the successor to LPV.
Yeah I have seen the ray-tracing solution but that will only work on DirectX 12 and Volta and later GPUs. AMD is currently working on a similar solution for their products and also Vulkan support. But this will take so much time to integrate to Unreal Engine for Epic Games and even then, most gamers as of today will not be able to use these settings because their hardware is too weak and I am not talking about old generation GPUs.
I think Epic Games should work on a real time dynamic global illumination. Not only because of us game developers but since they announced Unreal Studio, the benefit of real time lighting would result in more iterations of a project in less time and this would therefore lead to a better end project. And if a client wants to see instant results with different scenarios, models, textures etc, it would be easy to do since there is no need to wait to bake the lighting.
Epic Games showed RTGI (Ray-tracing Global Illumination) and RTAO at GDC 2018. But they said they did not used it in the Star Wars tech demo since it would require even more graphics power. So I dont know if they will release this. (watch at 25m 40s)
@Nocturness oh no you need 4x Volta cards!
even if RTX is usable in 4.20, and even if the NVIDIA guy expects games to ship with RayTracing technology later this year, I think it’s naive to think any of this will happen at the full extent of the technology (i.e at the level of the starwars clip they showed). also they had a budget of 24 fps :rolleyes:
personally I think it will start with raytraced reflections used on a really limited case by case basis (i.e. similar to planar reflections nowadays) and it will slowly grow from there
about the VXGI video you linked: yes it runs but not even smoothly (the guy states ‘i got 9 fps all lights on at begining’ in the video description), and this is but a small scene which is basically a tech demo and not a full production game
@CryRealUnity he actually mentions them using the volumetric lightmaps. unless I’m mistaken this means they used… baked lighting :eek:
Doing that would close down UE4 source code, they can’t share engine source if they have third party stuff attached.
That would be very bad step backward and they would have to pay for enlighten somehow, even worse, the bill would be passed down to engine users just like Unity does. This is why these days it’s so expensive to work with Unity and you can’t have free access to its source code.
not that I think Enlighten would be beneficial, but some stuff can be linked as a dll so you don’t need to share the engine source for it. I believe PhysX works like that
Enlighten only works with static objects, only the lights can move around, if an object is moving then it uses the standard lighting probe system. In my experience Enlighten is much slower to build lighting than Lightmass in UE4, and it’s pretty buggy. Unity also doesn’t have a distributed rendering system.
I was really hoping for news on VXGI as well, as the conference description for “Advances in Real-Time Voxel-Based GI” made some bold claims:
VXGI in VR on present day graphics hardware. Yet there doesn’t seem to be anything posted about the conference, just a bunch of hype about RTX which is only ready for Hollywood filmmakers, certainly not VR.
Huh. So maybe it’s not as helpful as I thought from reading the marketing materials (I swear that has never happened before).
So what options do we have for dynamic GI with indirect shadows?
Volumetric lightmaps: Ok indirect shadows but baked lighting
LPVs: Not really functional?
VXGI: Dynamic indirect lighting but shadows can be blocky?
I dunno, is VXGI the only option right now if you want both? And I assume you can’t use indirect capsule shadows with VXGI since they depend on baked lighting?
VXGI is the best quality available in UE4 right now, I’m not sure how the performance compares to LPV but I think LPV is so incomplete that it’s not really usable.
It also depends on what game you’re making, LPV can run on PC and console and it can be OK for an outdoors game (where you just need some extra lighting effects in the shadows) but VXGI will give better results and works much better for interiors and I think it supports more lighting options. But VXGI only runs on PC.
You can carefully tailor VXGI depending on the system you’re targetting, but be prepared to dedicate a significant portion of your GPU budget to it. It’s cost is also linked to scene complexity, so having enormous open worlds or small busy scenes will ruin it. If you’re shipping to anything other than PC, forget about DGI completely.
LPV does work, but it’s limited and you’ll have to design around it. Typically it works best for smallish outdoor games. Lionhead used it on Fable Legends for example, before it was cancelled.
Unless you have a rendering programmer on your team, be prepared to either spend a lot of cash on someone who can implement a bespoke solution for your game, or consider redesigning without it. DGI is still a cutting-edge technology even in 2018 (despite the very vocal opinions of some users), generally it’s better to spend that performance elsewhere.
Long story short, realtime GI is too inhibiting to be practical. Dynamic GI is still an extremely high-end PC-only feature for all engines. It might be better to figure out how to get Lightmass scenarios, or a full dymamic path without GI to work.
