Bullet requires collision shapes to be centered on the origin. OSG models do not necessarily have to be centered on the origin and often are not. You might need to account for this difference using a translation in your own code, so that the collision shapes coincide with the OSG visual representation of the collision shapes. Paul Martz Skew Matrix Software LLC http://www.skew-matrix.com <http://www.skew-matrix.com/> +1 303 859 9466
_____ From: [email protected] [mailto:[email protected]] On Behalf Of Fabian Aichele Sent: Thursday, January 15, 2009 1:10 AM To: OpenSceneGraph Users Subject: [osg-users] Choice of body-specific coordinate system origin by dae(COLLADA) reader Hello, osg-users! I have a question regarding the choice of the body-specific coordinate system made by the COLLADA reader (daeReader/Writer in osgDB). When I import a geometry from a COLLADA document, the osgDB plugin returns a osg::Group that contains the "nodes" declared in the COLLADA document together with all the "geometries" used by the node declaration, plus material properties etc. That works fine, but there is one thing I haven't figured out yet: How does the COLLADA importer decide where to put the "local" origin for a node hierarchy imported from COLLADA? I have tested different geometries consisting of 20 to about 50 triangle strips/fans/arrays, but the body-specific coordinate system was chosen quite arbitrarily (at least I couldn't figure out any pattern). This is important for me to know since I use OpenSceneGraph to visualize a rigid body simulation with the Bullet Physics engine, and I haven't managed to get the OSG and Bullet coordinate systems "in sync". Any hints or pointers to documentation/examples/earlier questions regarding this are gladly accepted. Thank you! Fabian Aichele
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