Why do we need tesselation for curved surfaces?

[zlatan]

Do devs with experience from tessellation on the 360 have any advantage when moving to DX11 tessellation?

The Xbox 360 tessellation model is not useful for most use cases. There are too many problems with the implementation. Very few developers use it.

 

[Spjut]

The Xbox 360 tessellation model is not useful for most use cases. There are too many problems with the implementation. Very few developers use it.

Ok thanks, interesting to know. I know Viva Pinata and Halo Wars used it for the terrain, and Banjo Kazooie for the water, but not of any other games.

I've always thought the PS3 not having one, and it not being in the DX9-10.1 spec was the biggest reason.

 

[SirPauly]

It's true in an ideal world where developers just make games for the PC. But most games are multi-platform.

Indeed!

 

[RussianSensation]

RussianSensation: These articles are just for PR.
It's true in an ideal world where developers just make games for the PC. But most games are multi-platform.

Ya, that's a fair point. But that's exactly why tessellation right now is inefficient, expensive to code/requirement to design many pre-tessellated assets and unnecessarily taxing on GPUs since it is not adaptive. It hasn't reached the adaptive/dynamic level that was promised and instead raised artistic costs and hampered GPU performance exponentially in many games without a tangible increase in visuals.

For example, in the Secret World, the game actually looks worse with tessellation On than Without.

Performance hit is nothing short of eye popping.

1080P Tessellation Off
GTX680 = 96 fps
HD7970 = 91 fps

1080P Tessellation On
GTX680 = 53 fps (-45%)
HD7970 = 24 fps (-74%)

If artists can't make a game look better with tessellation on, they shouldn't even touch this feature at all, when the result is a 45-74% slower game that looks worse.

 

[ViRGE]

For example, in the Secret World, the game actually looks worse with tessellation On than Without.

Holy hell that's awful!

 

[RussianSensation]

Holy hell that's awful!

Yup, and you get a 45-74% performance hit on $400-500 GPUs as well.

Nearly every object in today games is low poly. It's start with walls and end with small objects like cups. The only reason we don't see so many games using Tessellation Crysis 2 and HAWX2 is because of AMD's useless hardware. There is not one Gaming Evolved title on the market which is showcasing Tessellation.

Yes, AMD's hardware cannot run extreme tessellation Crysis 2, or in Batman AC. Looks like you are right that AMD's hardware is totally worthless for Tessellation....:sneaky: and people wonder why this thread went downhill so fast.

Crysis 2 on Ultra
Batman AC maxed out

Even HD6850 provided perfectly playable framerates in HAWX 2 with tessellation:

There must be reasons other than "AMD's worthless hardware" why Tessellation is not taking off:

1) Current generation consoles are not DX11 capable, and cannot do tessellation. That means to add these DX11 features you need to code the game for the PC from the ground-up or add a DX11 patch later ala Crysis 2. Both of these options add extra costs to game development that not all studios can justify.

2) Artistic and development costs overall due to lack of adaptive/dynamic tessellation model in place for now can force project delays and cost overruns;

3) Developers are still struggling to use Tessellation efficiently and especially having a lot of difficulty with using this feature to make games look tangibly better (Crysis 2, Metro 2033, The Secret World, STALKER: COP).

4) Modern GPUs in general are too slow period to use tessellation outside of select areas. Neither GTX680 nor HD7970 will be fast enough to run an entire tessellated game world with in-game characters, while using all the other advanced graphical features such as Boken Depth of Field, SSAA/HDAO, multiple area lights, global illumination model via DirectCompute shaders, contact hardening shadows, volumetric fog, POM, etc. It's pretty funny that you are blaming "AMD's worthless hardware" for stopping tessellation from taking off when tessellation is just in its infancy and 225+ million console games cannot use this feature, making it prohibitively expensive to code games with DX11 pre-tessellated assets until PS4/Xbox720 launch and start using Unreal Engine 4, CryEngine 3.4, Frostbite 2.0 game engines, etc.

 

[SirPauly]

IF one doesn't like the performance hit, ya know, one can turn it off.

 

[Keysplayr]

IF one doesn't like the performance hit, ya know, one can turn it off.

As is the case with just about any gaming image quality or immersive option.

 

[blackened23]

IF one doesn't like the performance hit, ya know, one can turn it off.

Of course! But I do agree that the reason more titles do not feature tessellation is due to consoles. Consoles are the priority in multiplatform titles and with that being the case, tessellation can be a hard sell. This will all change next year with new consoles, I believe. Trust me, i'd love it if every title featured tessellation, while I love games like darksiders 2 / dark souls the quality of the PC ports makes me cringe. The textures and IQ are for the most part, awful - with some DX11 features to spice it up it would be oh so much better.

 

[SirPauly]

imho,

Moving forward is hard -- nit-picking is easy! The key is tessellation is in DirectX 11 and titles are starting to offer the ability! Are the examples ideal for all? Absolutely not but there is a lot of good there; and as hardware, software and developers improve on the use of tessellation things may improve moving forward.

 

[RussianSensation]

IF one doesn't like the performance hit, ya know, one can turn it off.

You seem to have missed the part about how tessellation was supposed to make games look better. I am OK with a 50% performance hit if it actually makes good use of tessellation. Secret World is NOT one of those cases. It's just another example of how tessellation is poorly implemented technique today. I am hoping Crysis 3 will change this as it is rumored to use adaptive tessellation and vegetated tessellation. If Crysis 3 with extreme tessellation looks miles better, I won't mind if my 7970 chugs at 25 fps, but if it has tessellated the entire dam and every tree and they look almost the same, or worse (Secret World cough, cough), then you already know my opinion.

 

[futurefields]

Once done properly we'll actually see both an improvement in IQ and performance.

The last thing hardware vendors want to do is increase performance on stuff you have already paid for. If anything they will wait for a new API that will force you to buy a new GPU with a different architecture before they optimize anything.

 

[Red Hawk]

Of course! But I do agree that the reason more titles do not feature tessellation is due to consoles. Consoles are the priority in multiplatform titles and with that being the case, tessellation can be a hard sell. This will all change next year with new consoles, I believe. Trust me, i'd love it if every title featured tessellation, while I love games like darksiders 2 / dark souls the quality of the PC ports makes me cringe. The textures and IQ are for the most part, awful - with some DX11 features to spice it up it would be oh so much better.

Darksiders 2 supports DirectX 11, according to the Wikipedia list of DX11 games. There's no renderer switch or visual improvement over the console versions to be found though. I would guess they used DX11 to improve performance much like World of Warcraft did.

 

[WMD]

Ya, that's a fair point. But that's exactly why tessellation right now is inefficient, expensive to code/requirement to design many pre-tessellated assets and unnecessarily taxing on GPUs since it is not adaptive. It hasn't reached the adaptive/dynamic level that was promised and instead raised artistic costs and hampered GPU performance exponentially in many games without a tangible increase in visuals.

For example, in the Secret World, the game actually looks worse with tessellation On than Without.

Performance hit is nothing short of eye popping.

1080P Tessellation Off
GTX680 = 96 fps
HD7970 = 91 fps

1080P Tessellation On
GTX680 = 53 fps (-45%)
HD7970 = 24 fps (-74%)

If artists can't make a game look better with tessellation on, they shouldn't even touch this feature at all, when the result is a 45-74% slower game that looks worse.

The stone walls and buildings in witcher 2 looks great and runs great without tessellation.

 

[f1sherman]

Holy hell that's awful!

Dragon Age 2 has radius around your char with everything outisde this radius not receiving tessellation. Iit's really awful seeing this radius moving with your character while walking.

Crysis 2 is still the best looking and most ingame-widely implemented tessellation yet. Torches and pitchforks notwithstanding.

 

[SirPauly]

You seem to have missed the part about how tessellation was supposed to make games look better. I am OK with a 50% performance hit if it actually makes good use of tessellation. Secret World is NOT one of those cases. It's just another example of how tessellation is poorly implemented technique today. I am hoping Crysis 3 will change this as it is rumored to use adaptive tessellation and vegetated tessellation. If Crysis 3 with extreme tessellation looks miles better, I won't mind if my 7970 chugs at 25 fps, but if it has tessellated the entire dam and every tree and they look almost the same, or worse (Secret World cough, cough), then you already know my opinion.

I don't allow idealism to be the enemy of good!

 

[Red Hawk]

Dragon Age 2 has radius around your char with everything outisde this radius not receiving tessellation. Iit's really awful seeing this radius moving with your character while walking.

Really? Never noticed that. It seems like a sensible implementation of tessellation though, establishing a radius after which objects do not get tessellated. No point in giving fine detail to objects you aren't even close enough to appreciate.

Though there are other problems with DA2's tessellation implementation. Namely, wall tessellation tends to have a perceptible line along the silhouette of the tessellated object, and the characters' feet sink into floor tessellation as if it wasn't there (though non-tessellated floor geometry seems to have that problem sometimes as well, so I don't know if that is a tessellation-specific problem).

Crysis 2 is still the best looking and most ingame-widely implemented tessellation yet. Torches and pitchforks notwithstanding.

By "ingame-widely implemented", I assume you mean "implemented with little to no visual improvement half the time"?

 

[RussianSensation]

If you guys don't mind using Google Chrome translator, this article looks at some upcoming Fall 2012 PC game titles.
http://gamegpu.ru/action-/-fps-/-tp...2-sovremennym-videokartam-prevyu-gamegpu.html

Hitman: Absolution looks like it'll be a fun game!

Most of these games are going to be DX11, even Black Ops II it seems. Not seeing anything about abundant tessellation use in any of these titles though. Medal of Honor Warfighter and Far Cry 3 look like the graphical stand-outs to me.

 

[SirPauly]

The key is tessellation is actually being added and the developers are trying to raise the bar.

From Secret World:

http://www.notebookcheck.net/uploads/pics/1366highc_01.jpg

http://www.notebookcheck.net/typo3temp/pics/deed5a251f.jpg

Of course the sponsored titles are going to offer the tessellation that best suits an architecture but tessellation is still being added -- creates awareness for tessellation, DirectX 11 as a whole and for the PC platform -- bigger picture than just AMD or just nVidia to me.

 

[BenSkywalker]

Honestly screw tessellation. We have nowhere near the hardware to run everything tessellated. By the time we do maybe we can have games using ray tracing.

That could deliver true to life visuals in gaming and looks to be far more promising than anything tessellation has done.

Ray Tracing will make tessellation pretty much mandatory(you could fully model all the detail, that would also work). Right now we use a whole bunch of shader hacks to simulate surface detail, ray tracing will break all of them. Dot3(or I guess normal maps is what the kids are calling them these days) fails, diffuse shaders fail, pretty much all the tricks we use to simulate things fail when we turn ray tracing on.

 

[blackened23]

The key is tessellation is actually being added and the developers are trying to raise the bar.

From Secret World:

http://www.notebookcheck.net/uploads/pics/1366highc_01.jpg

http://www.notebookcheck.net/typo3temp/pics/deed5a251f.jpg

Of course the sponsored titles are going to offer the tessellation that best suits an architecture but tessellation is still being added -- creates awareness for tessellation, DirectX 11 as a whole and for the PC platform -- bigger picture than just AMD or just nVidia to me.

There's a good argument that getting devs to do this now will give them a head start before next gen consoles launch - technically its not easy to add, and if they get familiar with it now it'll be that much better for them once the 720 and ps4 ship. On the flip side of the coin, I understand they would have to do different assets for both PCs and consoles. Its a tough call I guess. I know square enix is doing tessellation in most of their games, hopefully other big studios will follow suit.

Like I said, I would love for more titles to have tessellation, so many PC ports are very technically disappointing even if they're great games (mass effect 3, darksiders 2, dark souls fall in this category)

 

[RussianSensation]

The key is tessellation is actually being added and the developers are trying to raise the bar.

From Secret World:

http://www.notebookcheck.net/uploads/pics/1366highc_01.jpg

http://www.notebookcheck.net/typo3temp/pics/deed5a251f.jpg

Of course the sponsored titles are going to offer the tessellation that best suits an architecture but tessellation is still being added -- creates awareness for tessellation, DirectX 11 as a whole and for the PC platform -- bigger picture than just AMD or just nVidia to me.

See what I mean. In the 2nd screenshot with tessellation, those cobble stones look like small pillows/pouches sticking out of the ground. The 1st screenshot is actually a far more realistic representation of how a cobble stone road looks like. They are adding extra geometry and the game starts to look more cartoonist! While I am all for tessellation, the current implementation leaves much to be desired in terms of realism. Just like PhysX actually, it makes things look too exaggerated I feel.

 

[Pottuvoi]

Though there are other problems with DA2's tessellation implementation. Namely, wall tessellation tends to have a perceptible line along the silhouette of the tessellated object, and the characters' feet sink into floor tessellation as if it wasn't there (though non-tessellated floor geometry seems to have that problem sometimes as well, so I don't know if that is a tessellation-specific problem).

DA2 doesn't use tesselation to near range geometry, it does use it for far away geometry using something similar to PN-triangles.
Cobblestones and walls use some sort of 'not so perfect' Parallax Mapping. (POM or other.)

There are several limitations with current DX11 tesselation so hopefully we will see advancements with DX12. (SM6)

Tesselation factor of 64 sounds like much, until you take a big wall and try to use it on big wall. (think great wall of china.)
All base meshes need to be pre tesselated to get decent quality. (64m wall without tesselation will get 1 vertex/meter resolution with maximum tesselation.)

Maximum tesselation factor should be a lot bigger (~n would be nice), while properly/easily allowing variable tesselation factor within a patch.

some nice sources on tesselation.
http://rastergrid.com/blog/2010/09/history-of-hardware-tessellation/
http://sebastiansylvan.wordpress.com/2010/04/18/the-problem-with-tessellation-in-directx-11/

On subject of small triangles and performance. (proposes possible solution which is not currently used on any hardware, perhaps on Maxwell?)
http://graphics.stanford.edu/papers/fragmerging/

 

[Arkadrel]

The 1st screenshot is actually a far more realistic representation of how a cobble stone road looks like.

Its funny because I looked at the pictures SirPauly posted from Secret World.
All I could think was:

1) Road without tessellation looks real, with the bricks/stones stomped down until road is leveled.
Where do you see roads where the bricks stand out of the road like that? in a modern city?
You dont, which means it doesnt look realistic. (which is what Secret world was aiming for = real city)

2) The picture with tessellation had FXAA on, and all the details/colours where washed out.
Dispite the picture without tessellation haveing more "jaggies" (and being a much lower
resolution) it looked better.

look at the whiteboard/advertisment in background of the pictures. You can almost make out the text in the non FXAA pic.
Look at the windows in the side, you can see lights inside the house/workshop.... in the FXAA picture, it looks like the windows are cardboarded up or something, not like windows.

 

[-Slacker-]

This part was a fun read:



So the anti-nvidia crowd got their shoes in the mouth...who would have guessed? ^^

Oh I see. You just HAVE to tessellate flat surfaces to hell because otherwise it causes shadow acne. Excuse me if I feel like I'll wait for an actual source on that article, I'm one of those pesky skeptics.