What is a 'large' terrain?

We can define the large terrain as follow : A terrain that a camera at a medium altitude can see 1/(10~30) of this terrain if camera look to the terrain perpendicular.

I hope u understand what i mean.

terrain is all a matter of apparent scale.

i'm doing a fps rpg where terrain is drawn out to about 1000 ft range (~300m). in that games distance scale, its 1000 d3d units. visual range for the game is considered to be something between 300 and 1000 feet (100-300m). ground quad size is 10 d3d units, and the ground is draw out to a distance of about 1000 d3d units from the camera, which in that game's scale is about 1000 feet or about 300 meters. the game world is 2500x2500 miles in size ( 4000 x 4000 Km ). the "ground mesh" for the entire world (if generated all at once from world map data) would be 87.12 trillion triangles. The game stores world map data, and generates chunks of the ground mesh on the fly as needed from the world map data. A chunk is 300x300 D3D units in size. "visible range" is 100 ground quads in all directions from the camera.

i'm also working on an airship flight sim. in that game, visual range for the largest objects is something ridiculous like 187 miles ( approximately 300 Km ). in that game, the ground quad size isn't 10 d3d units, its 50,000 d3d units! and the terrain is drawn out to a distance of 1 million d3d units from the camera. the game world covers the area between Chicago and Moscow. For now it uses "scrolling" terrain. I haven't decided how i'll do the ground in it yet. procedural chunk based, with the heightmap function dictated by actual terrain (so it generates mountains where the Alps are, etc) - unless i can get my hands on some good topo data. but "visible range" in this title is currently only 20 ground quads in all directions from the camera.

We can define the large terrain as follow : A terrain that a camera at a medium altitude can see 1/(10~30) of this terrain if camera look to the terrain perpendicular.

I hope u understand what i mean.

you mean a skycam view as used in an RTS or RTT type title would only show 1/10th to 1/30th of the world at once.

a "big map" like that shouldn't be an issue. it seems that everything becomes easy once you resort to chunking. well, maybe not easy, but probably doable at least.

Like my old hot rodder saying, "everything becomes easy once you resort to customization".

doable, even if you have to tessellate all possibly visible chunks ( chunk space partitioning anyone? ).

Thanks Norman Barrow complete and nice descriptions.

i'm also working on an airship flight sim. in that game, visual range for the largest objects is something ridiculous like 187 miles ( approximately 300 Km ). in that game, the ground quad size isn't 10 d3d units, its 50,000 d3d units! and the terrain is drawn out to a distance of 1 million d3d units from the camera. the game world covers the area between Chicago and Moscow. For now it uses "scrolling" terrain. I haven't decided how i'll do the ground in it yet. procedural chunk based, with the heightmap function dictated by actual terrain (so it generates mountains where the Alps are, etc) - unless i can get my hands on some good topo data. but "visible range" in this title is currently only 20 ground quads in all directions from the camera.

This work must be extraordinary thing.

Like my old hot rodder saying, "everything becomes easy once you resort to customization".

I agree with you.

i'm doing a fps rpg where terrain is drawn out to about 1000 ft range (~300m). in that games distance scale, its 1000 d3d units.

What is the name of this game?

I think combining the chunk with DetailTessellation11(DirectX sample) gives good result. what do you think??