Hi Alan, On a related topic, I have noticed that setting the track node to a model with variable geometry (i.e. a model with a particle emitter) causes the focus point to jump around a lot. I generally insert my loaded models into PositionAttitudeTransform nodes, and focus the node tracker on the PAT node. If the underlying model sub-graph has variable geometry (particle emitters in my case), the model appears to jitter. I believe this is because the center of the bounding sphere is moving due to the particles.
If we are going to modify the NodeTrackerManipulator as suggested below, would it benefit anybody else to allow the tracker to focus on the position of the PAT node rather than the center of the bounding sphere? Just a thought. Thanks, Justin From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dickinson, Alan J. Sent: Wednesday, July 09, 2008 1:21 PM To: [email protected] Subject: [osg-users] NodeTrackerManipulator doesn't appear to tracktransform nodes correctly? Hello, I have been working with the NodeTrackerManipulator class to follow a PositionAttitudeTransform node. When I setTrackerNode() for the PositionAttitudeTransform node everything appears to configure fine except the resultant center postion is incorrect for nodes which have there own transformation. The computeNodeCenterAndRotation calculates the localToWorld coordinates for this node which is the same as the bounds center for the node itself. Therefore the nodeCenter is equal to its transformed center multiplied by localToWorld again. I was able to fix the code for my case by changing: Method computeNodeCenterAndRotation() THIS: if (validateNodePath()) { nodeCenter = osg::Vec3d(_trackNodePath.back()->getBound().center())*localToWorld; } TO if (validateNodePath()) { osg::Node *node = _trackNodePath.back().get(); // Check if node is a transform node and just use its already transformed center osg::Transform* trans = dynamic_cast<osg::Transform*>(node); if(trans) nodeCenter = osg::Vec3d(trans->getBound().center()); else nodeCenter = osg::Vec3d(node->getBound().center())*localToWorld; } else nodeCenter = osg::Vec3d(0.0f,0.0f,0.0f)*localToWorld; This seems to work for my case but I don't know if this will work for all other cases. Should I modify the NodeTrackerManipulator class and submit the change via the submissions process or would somebody like to take a look at this and see if this works for all appropriate cases then submit the change. Thanks for you support on a great product. Alan Dickinson
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