As with any thing you want to use that is an offset from a value, you need to keep track of the offset and subtract it when you set the value. For ease with rigid bodies, compute the centroid in the rigid body frame (or apply the inverse transform to map a point in external coordinates) and then rotate the internal coordinates and subtract them before setting when you want to set the translational part of the coordinats later. Make sense?
If you don't care what centroid you use, just use the rigid body center (since it is currently a unwejghted centroid and will at most change to a weighted centroid).
On May 25, 2009, at 2:01 PM, Keren Lasker kerenl@salilab.org wrote:
> I know Daniel .... > This is how I solved it now - but I would like to change the > centroid of the rigid body after an optimization stage since it is > part of a bigger optimization protocol. > On May 25, 2009, at 1:54 PM, Daniel Russel wrote: > >> Assuming you want to transform, say, the input pdb, then just get >> the transformation immediately following creation and compose with >> that (since the initial transform has not moved the object). >> >> >> >> On May 22, 2009, at 10:27 PM, Keren Lasker kerenl@salilab.org >> wrote: >> >>> thanks - but what I want to do is different from RigidBodyMover as >>> the transformation should be absolute and not relative. >>> On May 22, 2009, at 9:40 PM, Dina Schneidman wrote: >>> >>>> it is rigid body internal coord. transformation. >>>> you can move by composing it with your move. take a look at >>>> RigidBodyMover.cpp propose_move func. >>>> >>>> On Fri, May 22, 2009 at 7:43 PM, Keren Lasker >>>> kerenl@salilab.org wrote: >>>>> >>>>> Is the transformation given in set_transformation relative to a >>>>> global >>>>> internal coordinate system or to the rigid body internal >>>>> coordinate system >>>>> ? >>>>> If the answer is that it is relative to the rigid body internal >>>>> coordinate >>>>> system -how can you move the rigid body to a specific position >>>>> in space ? >>>>> >>>>> Thank you ! >>>>> Keren. >>>>> >>>>> >>>>> _______________________________________________ >>>>> IMP-dev mailing list >>>>> IMP-dev@salilab.org >>>>> https://salilab.org/mailman/listinfo/imp-dev >>>>> >>>> _______________________________________________ >>>> IMP-dev mailing list >>>> IMP-dev@salilab.org >>>> https://salilab.org/mailman/listinfo/imp-dev >>> >>> _______________________________________________ >>> IMP-dev mailing list >>> IMP-dev@salilab.org >>> https://salilab.org/mailman/listinfo/imp-dev >> _______________________________________________ >> IMP-dev mailing list >> IMP-dev@salilab.org >> https://salilab.org/mailman/listinfo/imp-dev > > _______________________________________________ > IMP-dev mailing list > IMP-dev@salilab.org > https://salilab.org/mailman/listinfo/imp-dev