Why do we need tesselation for curved surfaces?

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Lonbjerg

Diamond Member
Dec 6, 2009
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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.


I didn't say that...nice fallacy :thumbsdown:
 

SirPauly

Diamond Member
Apr 28, 2009
5,187
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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/

Thanks, nice post!
 

Nintendesert

Diamond Member
Mar 28, 2010
7,761
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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.





A quick Google search will show you just how varied cobblestone roads and streets are. While some are flat, some are also much more rounded than even the second picture. I don't think it a very valid criticism of the technology when it simply doesn't adhere to your misconceptions of what something should look like.
 

Bobisuruncle54

Senior member
Oct 19, 2011
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A quick Google search will show you just how varied cobblestone roads and streets are. While some are flat, some are also much more rounded than even the second picture. I don't think it a very valid criticism of the technology when it simply doesn't adhere to your misconceptions of what something should look like.

Agreed. The cobblestone is fine, with the possible exception of the words painted on the surface, but it's difficult to tell from that screenshot. The brick wall on the other hand has a lot of problems, which is most noticeable on the corner.

It's a bit hit or miss at the moment, but when the next Xbox is released we should begin to see it used properly.

Does anyone have any info on UE4's implementation of tessellation by the way? I've watched the E3 footage of it but it doesn't seem to be discussed specifically.
 

Keysplayr

Elite Member
Jan 16, 2003
21,219
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Originally Posted by Nintendesert
A quick Google search will show you just how varied cobblestone roads and streets are. While some are flat, some are also much more rounded than even the second picture. I don't think it a very valid criticism of the technology when it simply doesn't adhere to your misconceptions of what something should look like.
Originally Posted by Bobisuruncle54
Agreed. The cobblestone is fine, with the possible exception of the words painted on the surface, but it's difficult to tell from that screenshot. The brick wall on the other hand has a lot of problems, which is most noticeable on the corner.

It's a bit hit or miss at the moment, but when the next Xbox is released we should begin to see it used properly.

Does anyone have any info on UE4's implementation of tessellation by the way? I've watched the E3 footage of it but it doesn't seem to be discussed specifically.

Thirded. I've seen pretty wicked cobblestone streets in Manhattan all gnarled up and blocks sticking up and uneven.
 

RussianSensation

Elite Member
Sep 5, 2003
19,458
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Italian cobblestone-covered street in Isola Bella. Cobblestones such as these are designed for horses to get a good grip.

Are there horses in the Secret World or is it populated by road cars?

A quick Google search will show you just how varied cobblestone roads and streets are. While some are flat, some are also much more rounded than even the second picture. I don't think it a very valid criticism of the technology when it simply doesn't adhere to your misconceptions of what something should look like.

The Secret World has cars in the game. That's why the cobblestone road in the game doesn't look realistic, which is why I noticed it. It's not any misconception on my part. Also, if you look in that 2nd screenshots, all the cobblestones are perfectly rounded at the top, one after the other, like buns from an oven. That is not how stones would look like even if they did stick out far from the ground. In the first screenshot, because the stones are flat and look old and washed out, it actually is far more realistic than having 1000 perfect shaped cobblestones on a street that has been abused by cars.

Various examples of cobblestoneroads on which cars can actually drive, not cobblestone roads on which horses were used:
Milestone%20Imports%20Copper%20Mountain%20porphyry%20street.JPG


Here is a street in London, England:
london-street.jpg


4770379343_b837be004b_z.jpg


Tallin, Estonia
105625-cobblestone-road-tallin-estonia.jpg


I am pretty sure the paved cobblestone roads (i.e., plenty of which can be found in Europe) on which cars drive are fairly flat, not perfectly sticking out 4-5 inches from the ground like they are in the Secret World. The first thing that jumped out at me is how unrealistic they look for a paved cobblestone road after having seen plenty of European cobblestone roads in person. This is no different than Extreme Tessellation setting in Unigine Heaven that makes the demo look worse than running it in Normal tessellation mode. It actually exaggerates all the tessellated assets in that demo beyond realism.

As I said earlier, if you look at how the developers utilized tessellation in other places in the game, it becomes obvious they just threw this feature half-baked:

Tessellation On vs. Without. All the stones are drifting away from the wall and blurring the textures. Also, if you notice the part of the street on which the main character is standing still uses flat cobblestone road, despite tessellation being applied to the building on the left. That shows a non-uniform use of tessellation which jumps out right away because you have a flat cobblestone street that uses normal displacement mapping and then a wall that is being tessellated. They either should have tessellated that entire scene or not done it all because now it looks "half-baked".
 
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Keysplayr

Elite Member
Jan 16, 2003
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I can get pictures of cobblestone streets in pristine condition as well. So can any of us.
But I don't think the reason for the pronounced cobblestones are to give horses broken ankles, nor do I think the secret world is real. I just think it's there to give more of an illusion of immersiveness even if it is a bit overdone. More depth. And you know what? It does.
 
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RussianSensation

Elite Member
Sep 5, 2003
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What I am saying is tessellation has good potential long-term but the way it's used now in many games is a hit and miss and I used Secret World as 1 example of how tessellation makes the game take a 45-74% performance dump on $500 GPUs and, at the same time, it makes the game looks worse in places. I am hoping tessellation will go a long way from this examples and actually makes games look more realistic.

This criticism was also levelled at HDR lighting when it first came onto the scene. While it was a revolutionary new technique, the first major game engine that let developers make it rain with HDR was Unreal 3. UE3 overused HDR lighting that resulted in most UE3 games looking ugly and shiny. Right now, it appears that these programmers/artists seem to be in their infancy in learning how to use tessellation effectively because like the first wave of HDR games, current usage of tessellation often looks exaggerated and unrealistic. As HDR improved over time, we then got HDAO/SSAO, etc. The next generation tessellation should be much better than the current "pre-tessellated asset" GPU wasteful implementation and I am hoping adaptive tessellation is the next step.
 
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SirPauly

Diamond Member
Apr 28, 2009
5,187
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Italian cobblestone-covered street in Isola Bella. Cobblestones such as these are designed for horses to get a good grip.

Are there horses in the Secret World or is it populated by road cars?



The Secret World has cars in the game. That's why the cobblestone road in the game doesn't look realistic, which is why I noticed it. It's not any misconception on my part. Also, if you look in that 2nd screenshots, all the cobblestones are perfectly rounded at the top, one after the other, like buns from an oven. That is not how stones would look like even if they did stick out far from the ground. In the first screenshot, because the stones are flat and look old and washed out, it actually is far more realistic than having 1000 perfect shaped cobblestones on a street that has been abused by cars.

Various examples of cobblestoneroads on which cars can actually drive, not cobblestone roads on which horses were used:
Milestone%20Imports%20Copper%20Mountain%20porphyry%20street.JPG


Here is a street in London, England:
london-street.jpg


4770379343_b837be004b_z.jpg


Tallin, Estonia
105625-cobblestone-road-tallin-estonia.jpg


I am pretty sure the paved cobblestone roads (i.e., plenty of which can be found in Europe) on which cars drive are fairly flat, not perfectly sticking out 4-5 inches from the ground like they are in the Secret World. The first thing that jumped out at me is how unrealistic they look for a paved cobblestone road after having seen plenty of European cobblestone roads in person. This is no different than Extreme Tessellation setting in Unigine Heaven that makes the demo look worse than running it in Normal tessellation mode. It actually exaggerates all the tessellated assets in that demo beyond realism.

As I said earlier, if you look at how the developers utilized tessellation in other places in the game, it becomes obvious they just threw this feature half-baked:

Tessellation On vs. Without. All the stones are drifting away from the wall and blurring the textures. Also, if you notice the part of the street on which the main character is standing still uses flat cobblestone road, despite tessellation being applied to the building on the left. That shows a non-uniform use of tessellation which jumps out right away because you have a flat cobblestone street that uses normal displacement mapping and then a wall that is being tessellated. They either should have tessellated that entire scene or not done it all because now it looks "half-baked".

Idealism with cobblestones, too. Is there no end? :)
 

Keysplayr

Elite Member
Jan 16, 2003
21,219
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What I am saying is tessellation has good potential long-term but the way it's used now in many games is a hit and miss and I used Secret World as 1 example of how tessellation makes the game take a 45-74% performance dump on $500 GPUs and, at the same time, it makes the game looks worse in places. I am hoping tessellation will go a long way from this examples and actually makes games look more realistic.

I've got a bit of news for you. AA is still hit and miss and it's been around since nearly the very beginning and developers are still trying to find better ways to do it.
Sorry RS, but your perfect world just doesn't exist yet and probably won't ever.
 

RussianSensation

Elite Member
Sep 5, 2003
19,458
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Idealism with cobblestones, too. Is there no end? :)

Good Sir, can you please be so kind as to not quote my entire post next time? You can just do
:thumbsup: Thank YOU :)

Sorry RS, but your perfect world just doesn't exist yet and probably won't ever.

Kesy, I am not asking for the perfect world. Asking for adaptive/dynamic tessellation that adds more realism as you get closer to the objects and varies the level of tessellation if you are farther away. I would gladly accept 75% performance hit if the visuals are an indisputable improvement (such as Unigine Heaven on Normal). Crysis 3, fingers crossed.
 
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Arkadrel

Diamond Member
Oct 19, 2010
3,681
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Just wanted to say that where I live we have cobblestone roads too in some cities.
Ive never seen any that look like they do in The Secret world. Where they all stick out of the road that much, their flatten out as much as possible in real life (because cars need to be able to drive on them, like RS said).

The problem is alot of games where they use tessellation, they go over the top, hopeing to be noticed for it (like this poorly implimentation of a cobblestone road). It doesnt add Image quality, if what you shoot for is realisme, but what you get instead is something cartoony.

I think its insulting people go "idealism with cobblestones, too. Is there no end?".
The secret world is supposed to take place in a modern day world, there are cars on the streets in it.
Why would there be cobblestone roads that look worse than they did a 1000 years from now?
At the very least, why dont they try to emulate the real world cobblestones as they are today?

A quick Google search will show you just how varied cobblestone roads and streets are. While some are flat, some are also much more rounded than even the second picture.

Like 4 pictures out of a 100 roads with cobblestone look as bad as those in the game,
and usually there arnt cars anywhere near them.

By that logic, its much much more common that roads of cobblestone look like the pictures RS posted.
 
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Bobisuruncle54

Senior member
Oct 19, 2011
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Good Sir, can you please be so kind as to not quote my entire post next time? You can just do :thumbsup: Thank YOU :)



Kesy, I am not asking for the perfect world. Asking for adaptive/dynamic tessellation that adds more realism as you get closer to the objects and varies the level of tessellation if you are farther away. I would gladly accept 75% performance hit if the visuals are an indisputable improvement (such as Unigine Heaven on Normal). Crysis 3, fingers crossed.

This is how I thought tessellation had to work in the first place, which would help eliminate the need for LOD models amongst other things, and therefore speed up and simplify production, not add complexity and time to it. As it currently stands does this mean that all tessellated assets are fully tessellated all the time?

Is this why the Unigine Heaven demo has that weird polygon morph effect at a certain draw distance, or is something else going on?
 

SirPauly

Diamond Member
Apr 28, 2009
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It doesnt add Image quality, if what you shoot for is realisme, but what you get instead is something cartoony.

I think it looks fine over-all and try to understand that the developer may be trying to bring more depth to some textures that some gamers may find appealing over-all. Thankfully, there is a turn-off setting if one doesn't like the performance or image quality. Hopefully, as the technology, hardware/software/developer mature there may be more efficiency and realism.

If some gamers enjoy the feature then it is a positive and did bring some good over-all.

Personally amazed that the debate became about a subjective evaluation of cobblestones.
 

Nintendesert

Diamond Member
Mar 28, 2010
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Just wanted to say that where I live we have cobblestone roads too in some cities.
Ive never seen any that look like they do in The Secret world. Where they all stick out of the road that much, their flatten out as much as possible in real life (because cars need to be able to drive on them, like RS said).

The problem is alot of games where they use tessellation, they go over the top, hopeing to be noticed for it (like this poorly implimentation of a cobblestone road). It doesnt add Image quality, if what you shoot for is realisme, but what you get instead is something cartoony.

I think its insulting people go "idealism with cobblestones, too. Is there no end?".
The secret world is supposed to take place in a modern day world, there are cars on the streets in it.
Why would there be cobblestone roads that look worse than they did a 1000 years from now?
At the very least, why dont they try to emulate the real world cobblestones as they are today?



Like 4 pictures out of a 100 roads with cobblestone look as bad as those in the game,
and usually there arnt cars anywhere near them.

By that logic, its much much more common that roads of cobblestone look like the pictures RS posted.




That is all well and good but still means there ARE cobblestone roads that do look like what the Secret World did. Whether or not that is the most accurate decision has absolutely nothing to do with the technology of tessellation.

RS made the point that tessellation created an inaccurate cartoony look, when in fact it is an accurate representation of certain cobblestone roads.

You cannot confuse misguided artistic or developmental decisions with poor technology. Now, had TSW developers attempted to make the cobblestone road look like most of city cobblestone roads and instead it turned out looking like the lesser seen cobblestone road then that would be a valid criticism of tessellation.

Instead what we have is akin to developers putting a WWI biplane in space flying by Saturn instead of using a space probe. The technology in rendering the biplane is not in question simply the decision to use a biplane.

That is no different than TSW using a Romanesque type cobblestone road in a contemporary city instead of a more contemporary style cobblestone road. If TSW developers tried to do a contemporary style cobblestone road however and the technology behind tessellation didn't allow that, I will stand corrected. :)
 

BenSkywalker

Diamond Member
Oct 9, 1999
9,140
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Asking for adaptive/dynamic tessellation that adds more realism as you get closer to the objects and varies the level of tessellation if you are farther away.

Geometric LOD, we've had it for years now

http://rastergrid.com/blog/2010/10/gpu-based-dynamic-geometry-lod/

Ideal HSR is a much larger factor then geometric LOD, but geometric LOD certainly helps. Problem we have is that developers don't always use tesselation with geometric LOD(which we have been using for many years). Sometimes when people start using a new feature, they focus too much on it while forgetting the fundamentals of rendering(sloppy, lazy coding).
 

Arzachel

Senior member
Apr 7, 2011
903
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That is all well and good but still means there ARE cobblestone roads that do look like what the Secret World did. Whether or not that is the most accurate decision has absolutely nothing to do with the technology of tessellation.

RS made the point that tessellation created an inaccurate cartoony look, when in fact it is an accurate representation of certain cobblestone roads.

You cannot confuse misguided artistic or developmental decisions with poor technology. Now, had TSW developers attempted to make the cobblestone road look like most of city cobblestone roads and instead it turned out looking like the lesser seen cobblestone road then that would be a valid criticism of tessellation.

Instead what we have is akin to developers putting a WWI biplane in space flying by Saturn instead of using a space probe. The technology in rendering the biplane is not in question simply the decision to use a biplane.

That is no different than TSW using a Romanesque type cobblestone road in a contemporary city instead of a more contemporary style cobblestone road. If TSW developers tried to do a contemporary style cobblestone road however and the technology behind tessellation didn't allow that, I will stand corrected. :)

Please show me a cobblestone road that looks like a thousand fuzzy gray balloons, please.

But that's missing the point. Why the hell use tessellation on mostly flat surfaces when you could use the tech on character and enemy models or anything else that could use the additional polygons. Why walls? Unless you're a fuzzy masonry affectionado, the 50-75% performance loss is insane.

SirPauly can go on about how idealism shouldn't get in the way of good, but this is plain bad.
 

Keysplayr

Elite Member
Jan 16, 2003
21,219
55
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Just turn it off if the performance hit is too great for your gpu. The exact same advice given for any eye candy feature. When AMD performs better in tesselation, you'll feel differently im sure. Then you could crank it up because, well, you just can.
 

Arzachel

Senior member
Apr 7, 2011
903
76
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Just turn it off if the performance hit is too great for your gpu. The exact same advice given for any eye candy feature. When AMD performs better in tesselation, you'll feel differently im sure. Then you could crank it up because, well, you just can.

Nevermind that you're basically calling me a fanboy made even funnier by the fact that I'm using a GTX 460 right now, how did you manage to strawman my post so hard?

I don't mind tessellation as a whole and don't mind the performance hit in itself, but TSW seems to be the first game I know, where an eye candy graphics option makes the game look worse and even if it didn't, they still chose the most pointless objects to tessellate.
 
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