In article <3EA2C68E.E34CE2DA@gmx.de> , Christoph Hormann 
<chr### [at] gmxde>  wrote:

> Reducing the problem of generating realistic terrain display to the
> requirements of 'flight simulator like' applications (meaning low
> resolution, large area, possibly realtime display of heightfield data)

Actually, today the terrain will be down to 1 meter or better resolution for
flight simulators.  But as it is created using air photographs, air radar
and satellites, it is always two dimensional data with height information.
While this does not cover 100% of the Earth surface, it covers well over
99.9%...

> does not cover this problem sufficiently.  As i have mentioned elsewhere
> in this thread terrain geometry is a very good example for a problem where
> procedural geometry can clearly be superior to the classical hand made
> mesh approach because terrain geometry is very complex but can be fairly
> well described algorithmically.

Yes, artificial geometry that creates true 3d surfaces will be easier this
way, but given all the advantages of terrain stored as height field for
simulations of real terrain, it is common to combine that information with
the 3d information only as needed.  Even for rendering, calculating an
artificial geometry at properly spaced point, scanline rendering will
outperform ray-tracing unless the ray-tracing algorithm handles the terrain
as a special case.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

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