On Nov 23, 2009, at 2:06 AM, Liam Browne wrote:

I want to rotate a model by 90 degrees about the axis of symmetry, but I seem to be having problems setting the axis correctly. After two identical models are superimposed I use measure rotation and get the following:

Matrix rotation and translation -0.04092271 -0.36724445 0.92922379 -82.20183653 -0.91203666 0.39354649 0.11537022 -54.21831923 -0.40806183 -0.84276490 -0.35104539 11.47082481 Axis -0.55288898 0.77167664 -0.31437070 Axis point -56.22800779 0.00000000 25.47389901 Rotation angle (degrees) 119.94780111 Shift along axis 0.00338820

What should I do to rotate the model at the same axis but by 90 degrees?

Many thanks, Liam

Hi Liam, You can just use the reported values -- the tricky part is remembering to indicate that they are in the coordinate system of the first model in the "measure rotation" command, and also using the reported axis point as the center of rotation. Let's say you used the command "measure rotation #0 #1". Then the values in the Reply Log are for the transformation of #1 relative to #0 expressed in the coordinate system of #0. <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/measure.html#rotation

Now you can use the values in the Reply Log to rotate #1 further. Keep in mind that this transformation will be applied on top of any existing transformations. If you want only the new rotation and not prior transformations, you would need to "reset default" first. To rotate model #1 90 degrees about the reported axis and use the reported axis point as the center, the command would be: turn -.55288898,.77167664,-.31437070 90 center -56.22800779,0,25.47389901 mod #1 coord #0 <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/turn.html> <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/reset.html> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco