Friday 2010-10-29 Dev. update and Discussion

[JAMF]

Originally Posted by Luftwaffepilot

Yes, but i was referring to the bomb craters, that will hopefully have a certain depth.
I think too that's impossible because that would be too much processing power needed.

There are other ways to achieve craters. A basic double pyramid with 6 sides only costs 16 triangles. Inverted, that looks like a hole. Graphic cards of today have a trick called tessellation. If the crater object was marked as an object that would receive tessellation, the card would increase that 16 triangles to 48, fo example. The crater now looks much smoother and the circular hole will have 12 sides.

Now add another trick, normal mapping (Dot3 bump mapping). Simplified, it's a texture, which tells the card to add extra height/thickness to a point on a model. Say white is very high/thick and black is nothing/zero. Lay a black&white noise texture over the crater and you get the inside surface to look like it's just exploded and it's covered with clumps of dirt and sand.

These effects should have little effect on the frame rate, as they can be distance-indexed, so they start to show only when you get closer. Similar to the LoD models aircraft have.

Bump mapping is an optical illusion, normal mapping really adds surface detail.

Left is bump-, right is normal-mapped. Notice the visual edge of the spheres:

[major_setback]

Originally Posted by JAMF

There are other ways to achieve craters. A basic double pyramid with 6 sides only costs 16 triangles. Inverted, that looks like a hole. Graphic cards of today have a trick called tessellation. If the crater object was marked as an object that would receive tessellation, the card would increase that 16 triangles to 48, fo example. The crater now looks much smoother and the circular hole will have 12 sides.

Now add another trick, normal mapping (Dot3 bump mapping). Simplified, it's a texture, which tells the card to add extra height/thickness to a point on a model. Say white is very high/thick and black is nothing/zero. Lay a black&white noise texture over the crater and you get the inside surface to look like it's just exploded and it's covered with clumps of dirt and sand.

These effects should have little effect on the frame rate, as they can be distance-indexed, so they start to show only when you get closer. Similar to the LoD models aircraft have.

Bump mapping is an optical illusion, normal mapping really adds surface detail.

Left is bump-, right is normal-mapped. Notice the visual edge of the spheres:

.


Oleg said a couple of times that craters will be bump mapped or similar (tessellation maybe), hopefully using the latest graphics technology for DX11.
I find it amazing what the new techniques can add to a flat modelled surface:


Video of tessellation on/off, a comparison:

http://www.youtube.com/watch?v=zdvZPIQpsQo

Tessellation explained:

http://www.youtube.com/watch?v=xPQ5Vy_5MP0

http://www.youtube.com/watch?v=-uavLefzDuQ

OFF/ON

[Freycinet]

Originally Posted by major_setback

.

Surely this is not just a difference between ON and OFF. Those are completely different 3D objects being shown. Don't think just adding tesselation will magically make roof tiles in the right shape. Or?

[SaQSoN]

Originally Posted by Freycinet

Surely this is not just a difference between ON and OFF. Those are completely different 3D objects being shown. Don't think just adding tesselation will magically make roof tiles in the right shape. Or?

No, this is the same 3d object. But on the lower picture, the usual normal (or bump) map is used as a displacement map in conjunction with the tesselation. Which, basically, produces the new 3D object "on the fly".

The thing is, however, that this is hardly of any use in flightsim (appart from the cockpit model and water visual effects), since from the distance, a player usually see other objects in-game, the normal map works as good, as this feature.

PS On a second thought, this feature also can be used for finer ground surface generation, where even a small bumps can be modeled.

[JVM]

Originally Posted by SaQSoN

No, this is the same 3d object. But on the lower picture, the usual normal (or bump) map is used as a displacement map in conjunction with the tesselation. Which, basically, produces the new 3D object "on the fly".

The thing is, however, that this is hardly of any use in flightsim (appart from the cockpit model and water visual effects), since from the distance, a player usually see other objects in-game, the normal map works as good, as this feature.

PS On a second thought, this feature also can be used for finer ground surface generation, where even a small bumps can be modeled.

If tessellation can be "activated " function of viewing distance it would add a lot of "lifelikeness" to objects like rail ballast and sleepers, road sides, craters, generally man-made objects like houses, buildings...maybe without taxing too much FPS!
I hope professional 3D people will be able to enlighten us sooner or later ...

[major_setback]

Originally Posted by JVM

If tessellation can be "activated " function of viewing distance it would add a lot of "lifelikeness" to objects like rail ballast and sleepers, road sides, craters, generally man-made objects like houses, buildings...maybe without taxing too much FPS!
I hope professional 3D people will be able to enlighten us sooner or later ...

I think SaQSoN is a professional.
Yes, I was also thinking of the railways...beaches (stones...rocks), cliffs. Even façades of bigger object buildings.

[Flanker35M]

S!

Tessellation is good for FPS games IMHO. Look at Metro 2033 and with high tessellation aka all DirectX 11 gimmicks on it brings to it's knees ANY of the new graphics cards. Really would you see from your 300mph+ speeding Spitfire or Hurricane cockpit if the stones of the railway would be bumped or not?

I really think tessellation could be dropped out of a flight sim that taxes the system hard enough without any more gimmicks to strain it even more. Sure, if an option for the screenie guys then sure, go for it. But if had to choose with it on at a 200+ plane engagement with decent FPS or horrbile FPS..no thanks.

Just my .2cents.

[SaQSoN]

Originally Posted by JVM

If tessellation can be "activated " function of viewing distance

This is exactly, how it works in the DX11, fully automatically. Basically, this feature replaces normal mapping feature. the later one is kind of "fake" 3D, which uses lighting effects to simulate small details. On the screenshot with the steam engine you can see "3D" rivetts, done with normal mapping. However, they only look 3D, while actually being flat.

Now, should the game support DX11 tesselation, at a certain distance (usually very close), the rivetts would become real 3D, in the following way: the polygon, this rivetts are painted on, would be tesselated into a HUGE number of a smaller polygons, which will be then displaced, using the same normal map as a displace map and form real 3D objects.

Originally Posted by JVM

it would add a lot of "lifelikeness" to objects like rail ballast and sleepers, road sides, craters, generally man-made objects like houses, buildings...maybe without taxing too much FPS!..

Actually, that is what normal mapping does quite well too. And definitely with bigger FPS (since there is much less polygons used).
As I said above, you would see distictive difference between displacement map and normal map only very close to the object. In a flight sim player very rarely sees objects that close (except cockpit, offcourse).

Originally Posted by major_setback

The picture: They are the same, but of course the model must be mapped in the correct way for the 3D effect to show...that is the wonder of this new graphics technology. It causes a lot less demand on your system than actual polygon modelling.

If a model is correctly made and mapped for use of normal mapping, it will not have to be remodelled to support tesselation+displacement mapping of DX11.
So, generally speaking, if someday Oleg's programmers will decide to include support of this technology into the game, his models will work well with it without any change.

[C_G]

re: tesselation;
Personally, I find the difference to be quite impressive.
But there are 2 concerns I have:
1- the fps hit.
If anyone has a DX11 capable card and a copy of the [-game-] [edit: Heaven benchmark] tesselation was demonstrated in, it would be interesting to know what impact the extra workload on the vid card caused (obviously while being played, not while taking still screenies).

2- can tesselation capability be easily laid over existing 3D models or does it require a complete rebuild?

C_G

[major_setback]

Originally Posted by SaQSoN

No, this is the same 3d object. But on the lower picture, the usual normal (or bump) map is used as a displacement map in conjunction with the tesselation. Which, basically, produces the new 3D object "on the fly".

The thing is, however, that this is hardly of any use in flightsim (appart from the cockpit model and water visual effects), since from the distance, a player usually see other objects in-game, the normal map works as good, as this feature.

PS On a second thought, this feature also can be used for finer ground surface generation, where even a small bumps can be modeled.

Oleg also mentioned that hedgerows might be 'mapped' in some way to give a 3D look, without having to model them. Bomb hole craters too maybe (as has been mentioned in this thread).

The picture: They are the same, but of course the model must be mapped in the correct way for the 3D effect to show...that is the wonder of this new graphics technology. It causes a lot less demand on your system than actual polygon modelling.
I think you need a dX11 compatible graphics card to enjoy the benefits of it.