9 Apr
2019
9 Apr
'19
4:17 p.m.
Hi, What's the origin for the rotation/translation output by measure rotation or fit-in-map results? If the origin index is 0, is the transformation calculated around (0, 0, 0)? I'm extending my software for transforming single-particle EM alignment parameters to accept a transformation matrix copy-pasted from Chimera and am having a slight difficulty. For most EM maps, the origin MRC header is not set, and the origin appears to be (0,0,0). Thus, if R and V are the rotation and translation from Chimera, the formula R * O + V - O where O is the real origin (boxsize / 2, boxsize / 2, boxsize / 2) should give the correct translation. However, it's exactly one pixel short. Best, -da