Glenn, I meant simple orthogonality relation between column vectors of localToWorld transform. First column represents local east vector, second local north, and third local up. computeLocalUp returns the same vector as third column of localToWorld transform. If computeLocalUp method gets changed, shouldn't computeLocalToWorldFromXYZ, computeLocalToWorldFromLatLonngHeight, be changed as well ? And then if we want to mantain column orthogonality it would require changes in computation of local north vector(second column).
Cheers, Wojtek Lewandowski ----- Original Message ----- From: Glenn Waldron To: OpenSceneGraph Submissions Sent: Wednesday, July 01, 2009 12:24 AM Subject: Re: [osg-submissions] EllipsoidModel::computeLocalUpVector IMHO: because getLocalUpVector() is a member of EllipsoidModel, it should respect the ellipsoid settings and return a vector orthogonal to the surface. Wojtek, I am not sure what you mean about killing the relationship b/w the up vector and the east/north vectors. Can you clarify this? Glenn Waldron : Pelican Mapping : http://pelicanmapping.com : +1.703.652.4791 On Tue, Jun 30, 2009 at 4:55 PM, Wojciech Lewandowski <[email protected]> wrote: Hi Ronald and all interested, I think you have touched a very delicate subject... But since You started it I will add my 2 pennies I agree that local coordinate system produced by EllipsoidModel has a bit unusual orientation. I did some investigation one day and it looks like this local coordinate frame is not tangent to ellipsoid surface. Instead local coordinate orientations correspond to tangent surface on a perfect sphere. But at least these orientation vectors in such spherical coordinate system are consistent. Local up vector is orthogonal to east and north vectors. If you change upVector method you will kill this relationship. I would be happy if we could use local space that would be tangent to ellipsoid but this would require not only changing localUp method but also changing worldToLocal and localToWorld methods. However, this sounds to me like problems with former osgDEM and VPB generated databases.... Frankly, I don't know what is best solution here. Maybe someone with GIS experience could provide some guidance. I think that we should ask for the answers to few simple questions : how the "up" vector should be defined ? As vector opposite to gravity vector ? Or as vector orthogonal to local east and north vectors ? Should the local north and local east vectors be tangent to the ellipsoid or not ? Cheers, Wojtek Lewandowski From: Maarseveen, R.A. (Ronald) van Sent: Tuesday, June 30, 2009 8:07 PM To: [email protected] Subject: [osg-submissions] EllipsoidModel::computeLocalUpVector Hi all, In OpenSceneGraph-2.8.2-rc2 in the file include/osg/CoordinateSystemNode Computing an up vector on an ellipsoid should take the geographic latitude into account. The geographic latitude is the angle between the normal to ellipsoid surface and XY-plane. The original code computes an upvector for a sphere. Best regards, Ronald van Maarsveen This e-mail and its contents are subject to the DISCLAIMER at http://www.tno.nl/disclaimer/email.html ---------------------------------------------------------------------------- _______________________________________________ osg-submissions mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org _______________________________________________ osg-submissions mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org ------------------------------------------------------------------------------ _______________________________________________ osg-submissions mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org
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