Hi, El Martes, 6 de Marzo de 2007 19:18, N. Farr escribió: > My understanding of PAT's is that they are groupings inside which all > objects are in a separate coordinate system different from the rest of the > scene. Should the PAT be placed at the root's (0, 0, 0), then its separate > coordinate system coincides with the world coordinate system, but if it > were to be moved around the scene using setPosition(), then the two > coordinate systems diverge. Despite this divergence, objects inside the PAT > will maintain their absolute coordinates, so an object that has > position (x, y, z) inside the PAT will maintain that position no matter > where we place the PAT itself. Is this correct? If so, is there a function > in OSG that can return an object's position inside the PAT in world > coordinates, not PAT coordinates? Finally, I would assume that what applies > to position applies to rotation, is that correct?
PAT nodes doesn't group anything, just transform the coordinates of the node or nodes hanging from it. Nodes by themselves haven't got a position or orientation, this is "inherited" from their "PAT" parents. So if you wanted to do what you said, a local frame where the objects are translated or rotated from it, you would have to chain at least two PATs: one for the mobile coordinate system and other PAT child to transform the object within it. world -> PAT (coordinate system) -> PAT (relative pos/orientation) -> object If you want to transform a coordinate from some node's local system to world coordinates or vice versa, you can use something like osg::Node::getWorldMatrices() to get the chain of transformations applied to that node. HTH, Alberto _______________________________________________ osg-users mailing list osg-users@openscenegraph.net http://openscenegraph.net/mailman/listinfo/osg-users http://www.openscenegraph.org/
