Hi Stephan,
On 2/8/07, Stephan Kussmaul <[EMAIL PROTECTED]> wrote:
We tracked down the problem and it is because of the optimization, which
is done when loading the database into the OSG viewer.
We have a MatrixTransform as parent of the whole scene, which moves the
terrain to it's place in world coordinate system. This matrix is baked
into the Nodes in the FlattenStaticTransformsVisitor, when loading to
OSG viewer. But as there are PagedLOD nodes to the extern referenced
tiles, those are not transformed and don't appear in place. Hmmm- is it
a bug or a feature? For our application we would have to insert a new
matrix over the PagedLODs.
This sounds like a bug. Making the MatrixTransform dynamic will be a
workaround, but a real fix will involved the
FlatenStaticTransformsVisitor being away of PagedLOD's and ProxyNode's
and not optimizing subgraphs with them in.
> What did you mean with the "s.th." above?
It's all about terrain ;-) Well, we could generate the island in higher
res for example for some stress testing.
Stress testing == good :-)
By the way: we are just holding all LODs of one tile in one .ive file,
which certainly isn't ideal for paging many LODs. What would you expect
to be a good policy for paging. How does osgTerrain do it for example?
Sorry, but I didn't familiarize myself with it yet.
Generally the best way to do paged database is is to build a quad tree
hierarchy with multiple levels of PagedLOD and associated res levels.
For some specific types of apps, such as ones that follow fixed paths,
such as road or a railway track it might be fine to have a relatively
flat structure, and not need to create losts of PageLOD levels, as
you'll never see the whole model at one time.
Robert.
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