coordinate update

coordinate update

Post by Giancarlo Amat » Thu, 12 Jun 2003 02:01:41



Hello Everybody,
I have the following problem:

how can I retrieve updated transformed coordinate? I mean I have a
SoTransform node, with a SoCoordinate3 and a SoCube. I move the cube with a
roto-traslation matrix which I defined in SoTrasnsform. Is my SoCoordinate3
object currently updated? If not have I to implement a matrix, vector
multiplication to obtain update coordinate?

Thank you for the help.
Giancarlo

--
================================
Dott. Giancarlo Amati
PhD student
University of Bologna (Italy)
Engineering Department
Phone: personal --> 328/2618525

================================

 
 
 

coordinate update

Post by Mike He » Fri, 13 Jun 2003 00:24:12



> how can I retrieve updated transformed coordinate? I mean I have a
> SoTransform node, with a SoCoordinate3 and a SoCube. I move the cube with a
> roto-traslation matrix which I defined in SoTrasnsform. Is my SoCoordinate3
> object currently updated? If not have I to implement a matrix, vector
> multiplication to obtain update coordinate?

Basically yes.

Open Inventor doesn't modify the coordinates stored in the scene
graph.  That would be very inefficient if the transform changed
frequently.  During a render traversal we send the transform to
OpenGL, then send the "raw" coordinates to OpenGL and let the
graphics hardware transform the coordinates.

If you have a path (SoPath) to the SoCoordinate3 node you can
apply an SoGetMatrixAction to this path to get the accumulated
transform matrix at that point in the scene graph, then use the
methods of SbMatrix to transform the coordinates.

-Mike
 TGS Inc, http://www.tgs.com

 
 
 

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