Hi Alex, I hope this does not change how the TransformerGraph of gui/vizkit3d visualizes the transformation matrices. Because from my point of view, the driver/transformer is the one which has a confusing way of interpreting transformations.
Transformation is just a matrix which express one frame with respect to another. That is all! Therefore, this is what we should specify in the transformer. Meaning that, for example: T_2_3 is a matrix which express frame_3 w.r.t frame_2. In algebra, it means the base of the subspace frame_3 is expressed (columns vectors) in the base of the subspace of frame_2. Another thing is what the user can do with such a matrix. For example: v2 = T_2_3 * v3 (v2 is vector expressed in frame2 and v3 is a vector expressed in frame_3). Which convert v3 into v2 and here is when the different interpretation comes. Thanks for the work, Javier. On 05/21/2014 10:27 AM, Alexander Duda wrote: > Hi, > > there is a change on master how vizkit3d interprets the transformer > configuration. The change is necessary because vizkit3d and > driver/transfomer were using different ones: > > Vizkit3d and driver/transformer are now using the following convention: > * All transformations are defined as SOURCE_IN_TARGET frame. > > Example: > static_transform(Eigen::Vector3.new(0.0,0.0,3.0), > Eigen::Quaternion.from_euler(Eigen::Vector3.new(Math::PI,0,0),2,1,0),"body" > => "world") > > Meaning: > The defined transformation T describes the transformation to convert > samples taken in a body coordinate system to a world coordinate system. > This is also the reason for its name body_in_world: > points_in_body*body_in_world=points_in_world > > At the same time the transformation T also describes the translation and > rotation to convert a world coordinate system to a body coordinate system: > body = world*T = world*world_to_body = world*body_in_world > world_to_body = body_to_world^(-1) = body_in_world > > Greets Alex > > _______________________________________________ Rock-dev mailing list [email protected] http://www.dfki.de/mailman/cgi-bin/listinfo/rock-dev
