-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello,
On 11/17/2013 06:42 PM, Mots G wrote: > Hi Paul, I'm confused between static and dynamic objects. Does > dynamic object mean the rigid body dynamic object and the dynamic > world? I thought dynamic objects were only needed if I had to get > inertia and motion states properties to the objects. In my case I > only need to test if the 3D models collide among themselves so > their movement(translations etc) could be restricted. These the classes objects Bullet is using: Static = never moves, doesn't get any collision response (think landscape or buildings), but other objects hitting it get collisions. Dynamic = both moves and gets collision response (i.e. bounces off when hit), typically most of your mobile objects. Kinematic = moves but doesn't get any collision response (it is not affected by impacts from other objects), but still will participate in the collision testing (can push away other objects, for example). Typically used for things that the user is manipulating. This is in order for the physics engine to not "freak out" because the object is moving differently than the physics expects it to. The reason for this type of division is optimization - e.g. two static objects never move, thus can never collide with each other and Bullet doesn't need to calculate such collision. Collision testing can be very expensive, that's why this optimization is there - to minimize the amount of calculation to be done. If you are getting a static-static collision, that either means that you haven't set the object type correctly for your moving objects or that you have two static objects overlapping - typically something like one piece of static decor (e.g. a building) overlapping another one (or even the ground!). > > Therefore I was under the impression only the collision library > (osgbCollision) would suffice my purpose. However I'm still missing > on something and unable to get it work. Bullet doesn't work like that. Even if you are using only the collision tests and not driving your objects using the physics simulation, you still must set up the object types correctly. Otherwise the collision engine will optimize the tests out or even fail with an error. In your case you must set the objects that you are moving as dynamic (perhaps kinematic) for the collisions to work. They cannot be all static. Regards, Jan -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iD8DBQFSiTgIn11XseNj94gRAixBAJ9PdzxAypWx4GU4x60gEmeXh27gSwCfZJEL Mefjrx+3c/ub8uxJeoxB7+8= =hH53 -----END PGP SIGNATURE----- _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
