[vtkusers] Re: Extending the VRML Exporter / Comment to vtkObject?

Rene Tschirley pooh at cs.tu-berlin.de
Mon Sep 23 11:25:20 EDT 2002

Hi again!

Obviously, my GPG software skipped the message part so here's my

----- Forwarded message from pooh -----

Hi all!

I believe I need to extend the VRML exporter and before I do it only for
my needs, I'd like to ask you all if you think that the extension is of
any interest for the community because I have no idea who wrote the
vtkVRMLExporter code.

My application creates an XML document which incorporates a VRML
object representing an isosurface of medical data. The XML document is
passed to another application (the viewer) which is responsible for the
presentation. For user interaction the viewer needs a set of hooks in the
VRML file to change e.g. a node's shape appearance. A usable hook would
be a name which can be defined by the exporting application. I could
simply name the nodes and tell the viewer the names outside the VRML
stream in the XML document. As far as I understand the exporter after a
first look, this might be a rather easy task as each actor is created
separately in a special method (vtkVRMLExporter::WriteAnActor).

The first idea is to enable each actor to carry a comment/annotation
character string which is used as a label to the transform node when the
actor is processed for VRML export (because the transform node is the
root node of a single actor and contains all the properties as well as
the point data). To realize this easily I would have to patch
vtkActor or better vtkLODProp3D.

At this time I thought if it would be useful to go to the root and enable
vtkObject to carry a comment/annotation. After this (as usual) I wonder
if there is already a way to realize this, but I didn't find an existing
solution or any vtk class that would fit my needs. I'd need a property
(the character string) which is applied to a vtkObject and could be read
out when the object is exported.

What do you think? A good idea or rather useless?


----- End forwarded message -----

Dipl.-Inform. René Tschirley              http://www.cs.tu-berlin.de/~pooh
TU Berlin, Computer Graphics and Computer Assisted Medicine research group

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