gamedevlists-general

[GD-General] Data format for terrain

[Michael V. <M.V...@gm...>]

Hello,

I was thinking about data formates which can be used for
large terrains like those, used in games like "Gothic"
or "The Elder Scrolls Oblivion". Of course, a heightmap
might be a good solution to store terrain data but the
disadvantage of a heightmap is that you don't have too
much control over the terrain. Another disadvantage is
that one cannot store additional information like normal
maps or other objects which are only used for small parts 
of the terrain (e.g. water surfaces, trees, buildings, etc) 
inside the heightmap.

A different approach would be to use a file format which
stores the heightmap data and all additional data in one
file.

A third approach would be not to use a heightmap at all.
Instead one could model the whole terrain using 3D Studio
or something similar. Of course, this would use lots of
memory since the model file could become extremely lage
(consider a world like the one of S.T.A.L.K.E.R. which
is incredibly large).

So, what do you think?

MfG
Michael
-- 


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Re: [GD-General] Data format for terrain

[Jon W. <hp...@mi...>]

Michael Varlik wrote:
> A third approach would be not to use a heightmap at all.
> Instead one could model the whole terrain using 3D Studio
> or something similar. Of course, this would use lots of
> memory since the model file could become extremely lage
> (consider a world like the one of S.T.A.L.K.E.R. which
> is incredibly large).
>   

We are just embarking on an update to our terrain system. We store the 
entire Earth, in a multi-resolution database format, where some parts 
(the ocean) are stored at extremely low resolution (a sample per 
kilometer, or worse), and other parts (like a city) are stored at much 
higher resolution. Currently, we store the database as a heightmap 
(based on a spherical geoid) with cultural models for buildings, 
vegetation, etc. We're looking into moving to a more flexible system, 
where different parts can be stored in different ways (i e, sculpt a 
cave with tunnels in 3dsmax; then layer a heightmap on top of that).

However, if you look at the amount of terrain data used by games such as 
Oblivion, World of Warcraft, etc, they don't mind putting more than a 
gigabyte of terrain data in their install -- so storing things as meshes 
is certainly possible. Interestingly, if you look at how those games 
render their terrain, they use tiles that are pieces of a heightmap -- 
then they add a lot of decoration on top. Oblivion, especially, goes in 
hard-core for the trees and ground cover, using the SpeedTree RT 
middleware package. Also, those games don't have a very far viewing 
distance -- out to a kilometer, at most. They compensate for this by 
using a wide-angle camera, so that the visible world still "looks" 
large. In our system, we currently have a viewing distance of 10 
kilometers, but instead have to trade off on detail.

I'll likely be able to publish some of the work we're doing on terrain 
now, so if you're hanging tight for another six months, I might be able 
to tell you in more detail :-)

Cheers,

             / h+