osgdem with is an tool the takes a moziac of imagery and dem's and generates a paged database. Its able to comfortable handle database of many gigabytes in size, the resulting databases run a solid 60Hz on most hardware with relatively light loads on both the CPU and the GPU. osgdem also handles geocentric databases, allow you to handle whole earth datasets.
Demeter is a CLOD alogrithm, and as such stresses the CPU and bandwidth to the GPU, times when I played with it it didn't perform well enough for real-time work (it was sub 60Hz). Scalability is also questionable, it might be able to handle 1k by 1k DEM, but what about a 10k by 10k? what about a 100k by 100k?
If we want real scalability then you have to use paged techniques such as osgdem provides. If you want to handle geocentric databases then you have to drop most many CLOD terrain implementation as they are based on flat earth assumption.
Robert.
On 10/3/06, [EMAIL PROTECTED] <
[EMAIL PROTECTED]> wrote:
Hi all,
I've been using OSG for, let's say, simple 3D graphics. But now it's time
to do a harder work!.
I need to draw a terrain model extracted from DEM files (or maybe other
formats imported by GDAL library).
I've seen that OpenSceneGraph has an utility called osgdem with which I can
generate a PagedLOD database of the terrain in osg format. And after that,
rendering this database is pretty simple.
But I have also noticed about Demeter, thinking at this moment that it
basically does the same thing that osgdem does, but doing it in real time,
I mean, Demeter gets all DEM files and generates terrain on-fly.
Anybody could clarify my point of view? Which one should I use to generate
terrain model?
Thanks in advance.
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Emilio Lozano Toro
Telvent
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