I cannot completely agree. I mean that I know that the real perfect bounding sphere is computationally expensive, but in many cases (solid objects) it should be computed just once (since BoundingSphere& node::getBound() checks if the bounding sphere has been already computed), when the object is created. The global bounding sphere might affect the fitting operation a lot. In case of objects like spheres or discs, the bounding sphere computed by OSG might be much greater than strictly required.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Simon Hammett Sent: martedì 11 agosto 2009 12.00 To: OpenSceneGraph Users Subject: Re: [osg-users] about the bounding sphere of a geode computed by OSG Calculating the perfect bounding sphere is an expensive operation. You need to calc the convex hull which is O(n log n). osg uses a fast approximation which is generally good enough. 2009/8/11 Gianluca Natale <[email protected]>: > Hi All, > Im having problem computing the global bounding sphere of my model. > I debugged OSG (2.8.0) and discovered that the bounding sphere of a geode > (BoundingSphere Geode::computeBound()) is > computed as the bounding sphere of the bounding box that includes all its > drawables !?! > > > > Why that? > > Shouldnt it be the global bounding sphere of the drawables, merging the > single bounding spheres > of all the drawables? > > > > So, a drawable that represents a sphere should have as bounding sphere > itself, > but this is not true with the computation OSG performs. It is larger than > strictly required. > > > > Thanks, > Gianluca Natale > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > -- http://www.ssTk.co.uk _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.392 / Virus Database: 270.13.49/2295 - Release Date: 08/10/09 18:19:00 _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
