3D Grass....Possible???

[pakotlar]

If we don't render realistic flora in games, some gamers may grow up not knowing what plants even look like. Either that or they'd have to go outside - and I'm not sure we should encourage that kind of thing.

Letting them outside would be a serious infringment on my moral code.

 

[Shark Sandwich]

Yes. It's ridiculous to say that Kameo and King Kong's grass are 2D. That's like saying a polygon in a 3D model is 2D when viewed orthogonally.

I disagree with this. A single polygon exists on a 2-dimensional plane. It is only when multiple polygons are connected in 3 dimensions that it becomes 3d. Say you have a cube. That cube is 3-dimensional, but each side of the cube when viewed alone is just a 2-dimensional square.

In the same way, if a blade of grass is confined to a single 2d surface, that blade of grass is 2-dimensional by definition. Only if that blade of grass curves around in 3d can it be considered 3-dimensional.

 

[SynapticSignal]

I disagree with this. A single polygon exists on a 2-dimensional plane. It is only when multiple polygons are connected in 3 dimensions that it becomes 3d. Say you have a cube. That cube is 3-dimensional, but each side of the cube when viewed alone is just a 2-dimensional square.

In the same way, if a blade of grass is confined to a single 2d surface, that blade of grass is 2-dimensional by definition. Only if that blade of grass curves around in 3d can it be considered 3-dimensional.

not if the poligonal grass can CURVE the surface when a player walk on this
this is 3d. period.

 

[Shark Sandwich]

not if the poligonal grass can CURVE the surface when a player walk on this
this is 3d. period.

Does the surface actually curve though? I was under the impression that it doesn't actually curve, it just tilts. If you take a flat 2d surface and tilt it to a different orientation, it is still a flat 2d surface. All the grass on that "sheet" is therefore still confined to a 2-dimensional surface at any given time. I'm sure it was done earlier than this, but I remember first seeing this technique used in Soul Calibur for DC and Tekken Tag Tournament for PS2.

 

[Titanio]

Why does grass have to be 3D?

When was the last time you people looked at a blade of grass?

Grass is rarely perfectly flat. It usually curves into the stem.

That asides having individual geometric blades versus quads with alpha-blended textures on them allows for a lot better physical modelling of the grass.

 

[MrWibble]

Grass is rarely perfectly flat. It usually curves into the stem.

That asides having individual geometric blades versus quads with alpha-blended textures on them allows for a lot better physical modelling of the grass.

I think the point was more about why you needed to be able to see that much detail in a game, rather than whether the current standard was particularly good.

I think if I was writing a golf game, I'd spend a lot of time getting the representation of grass to be very good. Assuming the physics model was also good, the player is going to want to get close to study each shot - they don't want to see a ball sitting on a perfectly flat picture of some grass.

An average FPS isn't going to require nearly so much attention to detail. Unless you're playing a sniper and have to lie down in grass a lot...

The original poster mentioned Unreal2007 where I really doubt very realistic grass would be a good spend of resources.

In rendering, I'd say it's possible to do much better than average for any given effect. However in doing so you'd have to trade something off - you can't have everything at once. It's all a matter of priorities, and I suspect that for most games, the grass will be low down the list. It's not that we can't, it's just that it's less important than sticking another couple of characters on screen, or giving them hair, or nicer HDR processing.

 

[flf]

Personally, I'm not terribly interested in good "up close" grass... I'm interested in good "far away" grass and groundcover. Most (if not all) games with a decent viewing distance have the grass as a near-field bit of fluff... and it only extends to a certain radius around the camera/player.

For example, it's always wonderful to think you're invisible laying down in tall grass, only to find out that when someone else looks at you from far away you're in the plain open, lying on a flat polygon in plain sight.

Give me a game that manages to pull off good waist-high grass from a distance and I'll be much happier than being able to see the detail of a single blade of grass up close.

 

[zidane1strife]

Still 3d grass can't be that expensive, it was used on a ps2 game, colored with a more realistic tone, it should be a breeze for these next-gen systems, it's ps2 lvl geometry. Especially when aiming for 30fps as it seems it's all the rage nowadays to focus on the detail.

 

[DeathKnight]

Are you all forgetting about the Nvidia grass demo for the original GeForce 256?

http://www.nzone.com/object/nzone_grassdemo_home.html

 

[Rodéric]

http://research.bytopia.net/OTS-GroundRenderer.zip
This is what I call 3D grass, not Impostors/Billboards/Sprites.

 

[purpledog]

http://research.bytopia.net/OTS-GroundRenderer.zip
This is what I call 3D grass, not Impostors/Billboards/Sprites.

Not the most beautiful grass I've ever seen...

I'm not sure what "3D grass" mean, but as long as you spend more than one draw call per grass, you're screw. Well, you can render some square meters if you want, but don't even dream of rendering large scale prairie. I'm sure there's more than 10000 blades per square meters, so when no way to render big prairie.

So it's not a question of having 3d grass or not, it's more a question of having the right level of detail for each distance: Nice 3d grass when you're close, billboards when you're further, and probably just a texture when you're even further. And of course, nice transition when the camera moves

To answer the original question, yes, next-gen stuff will have 3d grass, but it will most probably come along with other representations as well to keep polycount/fillrate low.

 

[zed]

grass ive been working on

gidday first post on these forums
ive been working on a vegetation system on and off for a few years, my aim is to replicate the grass used in cgi movies eg shrek. ie far better than anything that exists in current (or planned) games
http://uk.geocities.com/sloppyturds/grassA.jpg
stats/ ~50,000 blades of grass (each with a skeleton thus u can see a wind gust move through the field etc )
this is something u must see this in action and not judge it based on a static screenshot ( i may upload a video later )
unfortunatly u wont be seeing this level of detail in pc games for a few years, only the cell would have the power to pull it off at a reasonable framerate/quality ratio

 

[cloudscapes]

Real 3D grass is difficult and risky for developpers. It can probably be done (along with a LOD technique), but AA is pretty-much required. Withotu AA the ground would look like a chaotic noisefest, and since developpers are still porting games to lesser hardware (that can't use AA without a major hit) then they asses that it's just not time yet.

That's my take on it.

 

[ihamoitc2005]

Interesting

gidday first post on these forums
ive been working on a vegetation system on and off for a few years, my aim is to replicate the grass used in cgi movies eg shrek. ie far better than anything that exists in current (or planned) games
http://uk.geocities.com/sloppyturds/grassA.jpg
stats/ ~50,000 blades of grass (each with a skeleton thus u can see a wind gust move through the field etc )
this is something u must see this in action and not judge it based on a static screenshot ( i may upload a video later )
unfortunatly u wont be seeing this level of detail in pc games for a few years, only the cell would have the power to pull it off at a reasonable framerate/quality ratio

I would enjoy a video my friend. You have done much work. It is said MGS4 has 60,000 point physics for hair, with 50,000 blades of grass, how many points (vertices) will be used for physics?

 

[Xenus]

It's not so much it isn't doable more of developers don't want to waste all of their resources making 3d grass. It simply costs more than it is worth at the moment.

 

[zed]

video can be watched here
http://rapidshare.de/files/9313296/grassD.avi.html
u may notice one benifit of having seperate blades is it doesnt suffer as bad from the crappiness that all grass in games have when u look down at your feet and see the grass is infact a 2d polygon

It is said MGS4 has 60,000 point physics for hair, with 50,000 blades of grass, how many points (vertices) will be used for physics?

the above video has about 200,000 physics vertices onscreen at any one time
60,000 for the guys hair in MGS4 is easy doable with the cell,
this sort of thing is what it excels at compared to pcs
eg in the above video im calculating the physics + mesh creation + rendering each frame all on the cpu, with the cell u would devote one core fully to grass physics + one core fully to grass mesh creation (and prolly ramp the number of grass balades up to 1/4million) whilst leaving 5/6 cores to handle the rest of the stuff gamecode/physics etc

 

[purpledog]

It's not so much it isn't doable more of developers don't want to waste all of their resources making 3d grass. It simply costs more than it is worth at the moment.

R&D cost money, but some company are willing to invest in it. Grass, which come along with fur, is a good example of a technology which is not to hard to develop and give great visual feedback.

 

[Xenus]

R&D cost money, but some company are willing to invest in it. Grass, which come along with fur, is a good example of a technology which is not to hard to develop and give great visual feedback.

Wrong type of resources I was talking system resources. as in do you want a hundread enemies with grass as it is now or two with 3d grass. Before anyone asks those are arbitrary number pulled out of my behind.

 

[purpledog]

Wrong type of resources I was talking system resources. as in do you want a hundread enemies with grass as it is now or two with 3d grass. Before anyone asks those are arbitrary number pulled out of my behind.

Sorry for the confusion.

Anyway, IMO, the same remark apply here too. As you said, just a question of priority... Believe or not, some game company believe that a better natural immersion is something very important which will have some repercussion on the sells :smile:

But to be fair, I don't believe that grass/fur will be widespread until some tools comes along and simplify the job, (a bit like speedtree is doing for trees for instance).