RE: Static Objects in VRML Scenes

Steve Ghee (steve@division.co.uk)
Fri, 17 Nov 1995 16:26:49 -0000

I have found (and exploited) a 'feature' of Inventor in the scenes that
I am generating that allows (when viewed with Webspace on SGI or PC) =
some geometry to remain static in a scene while others can be moved. =
This allows text information to be statically displayed in the window =
while the rest of the vrml scene can be moved. The 'feature' is to add =
two cameras into the scene discription (which doesn't seem to be =
explicitly
forbidden by the spec for inventor or VRML, but the behaviour of which =
is
currently undefined) which has the effect of all geometry after the =
first
camera being handled as you would expect, while all the geometry after =
the second camera is rendered from the viewpoint of the second camera, =
but the second camera always remains static (hence static text/objects).
[...snip...]
I seem to remember reading a request from someone before for objects
that could esmain aligned with the viewing plane and I wondered if an
extension of this could be the solution.

The feature you describe is, of course, very dependant on the Inventor =
scene-graph model and may not be simple to simulate in other =
architectures.

The only sensible and extendable way to support this (IMHO) is to allow =
other nodes to be defined as children of Camera nodes - in this way, you =
can assign difserent geometry to difserent camera's, or use the USE =
command to replicate geometry if you have multiple camera's and want the =
same information. =20

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