Forgot to add: You also need the center of rotation, but I have assumed that this center point is already being stored as part of the data for the object from which the bounds are computed. If this is a standalone bounding box (for example, encapsulating a series of objects without a 'parent' object), then you would also require an additional 3D vector for the center point.
-- Matthew W. Fuesz Software Engineer Asc. Lockheed Martin STS 1210 Massillon Road Akron, OH 44315 [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Fuesz, Matthew Sent: Thursday, October 02, 2008 12:33 PM To: OpenSceneGraph Users Subject: Re: [osg-users] Bounding Parallelepiped For the case of a non-world-aligned bounding box - but still one which is parallel-sided (i.e., a rectangular volume) - you actually do not need all eight corners. You only need the two opposite corners (as osg::BoundingBox uses) plus a rotation. Thus, you require either 5 3D vectors (2 corners + 3x3 rotation matrix) or 2 3D vectors and 1 4D vector (2 corners + rotation quaternion). For a completely arbitrary bounding volume (where no two sides are guaranteed to be the same size), however, all of the corners would be necessary. -- Matthew W. Fuesz Software Engineer Asc. Lockheed Martin STS 1210 Massillon Road Akron, OH 44315 [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tomlinson, Gordon Sent: Thursday, October 02, 2008 12:26 PM To: OpenSceneGraph Users Subject: Re: [osg-users] Bounding Parallelepiped How OSG uses is fine for how it is used But we were not talking about HOW OSG uses but how a someone would like a bounding box that is not necessary axially aligned and to have a box were all six sides can be of difference size thus no real correlation between corners you need the 8 corners provide by opposite sides you cannot derive these if there all different Gordon __________________________________________________________ Gordon Tomlinson Product Manager 3D Email : gtomlinson @ overwatch.textron.com __________________________________________________________ (C): (+1) 571-265-2612 (W): (+1) 703-437-7651 "Self defence is not a function of learning tricks but is a function of how quickly and intensely one can arouse one's instinct for survival" - Master Tambo Tetsura -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Paul Melis Sent: Thursday, October 02, 2008 12:19 PM To: OpenSceneGraph Users Subject: Re: [osg-users] Bounding Parallelepiped Tomlinson, Gordon wrote: > I disagree :) > > You need 8 vec3's to do that, you need the 4 corners of any 2 opposite > sides of the bounding box in order to have every side a different size > > The osg::Bounding box only supplies 2 vec3's which effectively gives you 2 > corner points and you cannot get the 8 corner points from 2, apart from a > parallel rectangle ... > But using 8 corner points is reduntant, as OSG uses _axis-aligned_ bounding boxes. Even in case you were using aligned bboxes you would only need 4 vec3's to represent a bounding box under any orientation (one vec3 for one of the corners + 3 * a vec3 for each sizes axis starting at the corner (and even the 3rd axis could be deduced from the other 2, except for its length)). Paul > > > Gordon > > __________________________________________________________ > Gordon Tomlinson > > Product Manager 3D > Email : gtomlinson @ overwatch.textron.com > __________________________________________________________ > (C): (+1) 571-265-2612 > (W): (+1) 703-437-7651 > > "Self defence is not a function of learning tricks > but is a function of how quickly and intensely one > can arouse one's instinct for survival" > - Master Tambo Tetsura > > > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jean-Sébastien > Guay > Sent: Thursday, October 02, 2008 10:52 AM > To: OpenSceneGraph Users > Subject: Re: [osg-users] Bounding Parallelepiped > > Hi Gordon, > > >> Unfortunately, OSG does not directly support what you want as osg'S >> bounding box, is as you have seen is a axially aligned min/max LL/UR >> > > That is not true. OSG's bounding box supports separate xmin/xmax, ymin/ymax, > zmin/zmax values, so it can represent boxes that have different sizes on all > axes. > > However, as Robert explained, OSG uses BoundingBox on Drawables, but > BoundingSpheres on nodes. So if you just take the root node's bounding sphere > and put that into a bounding box, of course you will get a bounding *cube*. > > ComputeBoundsVisitor is what you need. It will compute a minimal axis-aligned > bounding box for all *drawables*, not using the bounding spheres. > > #include <osg/ComputeBoundsVisitor> > > osg::ComputeBoundsVisitor cbbv; > node->accept(cbbv); > osg::BoundingBox bb = cbbv->getBoundingBox(); > > It doesn't get much simpler than that. > > J-S > -- > ______________________________________________________ > Jean-Sebastien Guay [EMAIL PROTECTED] > http://www.cm-labs.com/ > http://whitestar02.webhop.org/ > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
