[Chimera-users] about model coordinates

Hi, I recently got a ~4.4A EM map and built a improved model using MDFF. The map and model is well aligned when loaded in Chimera. But it is off when I hit "center" in the volume viewer, as the origin is shifted. As I try to improve the model in Coot, the map and model isn't aligned at all in Coot, seemingly by the same offset when "center" button was hit. And also the values in the original index in the volume viewer is different from the values in the header in the density map. So I wonder what determines the origin index? and is it possible to find the shift and transform the coordinates in the model so as to align the model with the map in coot? Thanks a lot. Tc