you need to also include the translations (which is not needed for rotation of bvecs). You also need to know that the rotation-centre for eddy is the geometric centre of the volumes.
Right now we are working on extending eddy to intra-volume movement, which will make it even harder for external software to interpret the parameters from eddy. Instead we will aim att supplying tools that will use these parameters in the ways we can foresee
people wanting to use them.
Jesper
