Quaternions???

[mptak]

This may seem an odd place to put this but as I have looked at the Ruby methods for rotation they seem to be laid out very similarly to quaternion calculation which seem to be all the rage in robots and rockets. In the space of one week the word emerged in a number of discussions I read or watched particularly with regard to ROS and android and the neat little robot coming out of http://www.willowgarage.com. Since these discussions have been slow lately (except for the gems from Mr. K) I thought I would throw this one out there for now and then follow it up with some models and questions. PS. The best place I have found so far about the topic is http://www.euclideanspace.com.