[MasterDisaster]

I've heard, some time ago, an interview where epics admits that UE3 scales bad with MSAA turned on, because of his internal nature, There's any dev that can clear this concept?

[ShootMyMonkey]

Was the comment about MSAA in general or MSAA specifically on the Xbox360? The latter is a tiling problem, and UE3 was never built with that in mind. It is, after all, basically a PC engine that has some codepaths for consoles tacked on.

If it's the former... I don't know for sure just from your post.

[scooby_dooby]

Originally Posted by ShootMyMonkey

Was the comment about MSAA in general or MSAA specifically on the Xbox360? The latter is a tiling problem, and UE3 was never built with that in mind. It is, after all, basically a PC engine that has some codepaths for consoles tacked on.

If it's the former... I don't know for sure just from your post.

pretty sure it's in general, something to do with the way they do shadows.

[Powderkeg]

Originally Posted by ShootMyMonkey

Was the comment about MSAA in general or MSAA specifically on the Xbox360? The latter is a tiling problem, and UE3 was never built with that in mind. It is, after all, basically a PC engine that has some codepaths for consoles tacked on.

If it's the former... I don't know for sure just from your post.

I don't believe Epic ever said that tiling was the issue at all.

Sweeney- Gears of War runs natively at 1280x720p without multisampling. MSAA performance doesn't scale well to next-generation deferred rendering techniques, which UE3 uses extensively for shadowing, particle systems, and fog.

http://www.nvnews.net/vbulletin/showthread.php?t=70056

Seems to me like he was talking about all platforms, not just the 360. He certainly didn't blame tiling at all.

[MasterDisaster]

Originally Posted by ShootMyMonkey

Was the comment about MSAA in general or MSAA specifically on the Xbox360?

no, they are talking in general of the engine..

this is not a good thing, a lot of games will use UE3, I just want to know what's the problem of the engine and some effects when MSAA is active

[ERP]

It's been covered before, do a search, basically they reverse project screen space pixels into shadow space. So the cost of the shadows is proportional to the number of pixels prior to the downsample. So 2xMSAA doubles the cost of shadow rendering.

It strikes me there are several ways they could try and address this, but I have to assume that they tried them.

But UE3 doesn;t specifically limit you to any particular shadow approach, the app could easilly provide a different solution.

[MasterDisaster]

Originally Posted by ERP

It's been covered before, do a search, basically they reverse project screen space pixels into shadow space. So the cost of the shadows is proportional to the number of pixels prior to the downsample. So 2xMSAA doubles the cost of shadow rendering.

It strikes me there are several ways they could try and address this, but I have to assume that they tried them.

But UE3 doesn;t specifically limit you to any particular shadow approach, the app could easilly provide a different solution.

Understood..
But I think that the solution is not so simple as seems, looking the games when it come to direct-feed screens they all lack msaa

Cudos to you, thanks

[Brimstone]

I thought I read somewhere that nVidia is including a new A.A. method in the G80 to address this issue.

[ShootMyMonkey]

Sweeney- Gears of War runs natively at 1280x720p without multisampling. MSAA performance doesn't scale well to next-generation deferred rendering techniques, which UE3 uses extensively for shadowing, particle systems, and fog.

Ah... well if that was what he was talking about, that makes sense. I don't know for sure the specifics of Epic's own implementations, but getting back the light-space information for every sample like ERP mentioned is costly, and also you have some potential issues with certain types of data buffers anyway as regular old MSAA was meant for color and not everything behaves the same.

I think approaches like using a scaled light distance value would work just fine in many cases so long as the shadow is necessarily soft, but since they make a point of honor out of progressively softening shadows, that gets iffy.

[Guden Oden]

Considering how common UE3 looks to be on 360, I really think Epic should have gone out of its way to get MSAA to work fully on the hardware. It's an extremely important feature for image quality, and so much of the 360's GPU is built around MSAA support. To just throw that away... HMMM.

Alright, so occlusion techniques don't work well with MSAA according to Epic. Worst-case scenario, if another technique can't be found: just brute-force it then! Xenos has tons of fillrate. Some guy at Rare stated that Kameo's engine drew multiple copies of hundreds, if not thousands of on-screen guys by mistake with no drop in framerate. Let the hardware take it on the chin if neccessary so that we can have our MSAA.

[zed]

so UE3 uses deferred rendering? is there further info pertaining to UE3's use of it

[_phil_]

Originally Posted by zed

so UE3 uses deferred rendering? is there further info pertaining to UE3's use of it

Ue3 use defered Shadowing Only shadows are defered.

[Colourless]

Something to note, Bioshock is using UE3 and the screenshots released of it so far have AA. So either Irrational have been releasing highly supersampled bullshots or it's not an insummountable problem and it's possible to get MSAA to work... but we don't know what they've done to the engine

[Bohdy]

Originally Posted by Colourless

Something to note, Bioshock is using UE3 and the screenshots released of it so far have AA. So either Irrational have been releasing highly supersampled bullshots or it's not an insummountable problem and it's possible to get MSAA to work... but we don't know what they've done to the engine

BioShock uses a heavily modified UE2.5.

[Colourless]

/me does some more research...

Oh, it's seems it UE2.5 with some UE3 additions. Rendering engine is probably still UE2.5 based then.

[Platon]

Originally Posted by Bohdy

BioShock uses a heavily modified UE2.5.

Yeah, that is how understood it as well, a heavily modified UE2.5 but the toolset of UE3 ...

[MasterDisaster]

Originally Posted by Platon

Yeah, that is how understood it as well, a heavily modified UE2.5 but the toolset of UE3 ...

right, they are using vengeange engine (UE2.5 based) with portions of UE3 (as Splinter Cell: Double Agent and Duke Nukem Forever)

edit:
http://en.wikipedia.org/wiki/Vengean...ngeance_engine

[zed]

Originally Posted by _phil_

Ue3 use defered Shadowing Only shadows are defered.

so what do u mean? that the shadows are tacked on afterwards?
ie its not using, shadows == absense of light

[ERP]

Originally Posted by zed

so what do u mean? that the shadows are tacked on afterwards?
ie its not using, shadows == absense of light

No it just means what I started before, only the pixels that recieve shadows are shadowed. So the cost of shadowing is invariant with reciever geometric complexity.

This is done by reverse projecting the pixels from the front buffer into shadow space.

[Acert93]

Do a search people. ERP and others explained this in detail many months ago. ALL these questions are answered there

[Cyaneyes]

Originally Posted by Guden Oden

Considering how common UE3 looks to be on 360, I really think Epic should have gone out of its way to get MSAA to work fully on the hardware. It's an extremely important feature for image quality, and so much of the 360's GPU is built around MSAA support. To just throw that away... HMMM.

Alright, so occlusion techniques don't work well with MSAA according to Epic. Worst-case scenario, if another technique can't be found: just brute-force it then! Xenos has tons of fillrate. Some guy at Rare stated that Kameo's engine drew multiple copies of hundreds, if not thousands of on-screen guys by mistake with no drop in framerate. Let the hardware take it on the chin if neccessary so that we can have our MSAA.

As much as I like UE3, yet I am not a big fan of it. I can tell you that, in fact, Gears of War is -along with Forza 2, Halo 3, Alone in the Dark, etc- one of my favourite games and I am perfectly happy with it, but apart from that wonderful GoW, being it's the first UE3 game and all, the engine is full of some reproductivally inadvisable features. If nothing changes Epic will reproduce them quite a lot.

Taking into account what you stated about the amount of future UE3 games, imho, I truly hope Epic is looking into it.