ROTATE

ROTATE.TEX 6-dec-91

A SELECTION of ATOMS or POINTS is ROTATED around a point in space (CENTER). The ROTATION is specified via an MATRIX (in case of ATOM or POINT rotations) or as ROTATION around a BOND.

Syntax 


ROTATE BOND atom-num1 atom-num2 (atom-num3) -
              (SELECT CUT atom-num1 atom-num2 END )
               SELECT ... END
               ANGLE real



        ATOM  SELECT ... END
              MATRIX inte
              CENTER ATOM atom-num
                     COORDINATE  3*real
                     CALCULATED



        POINTS   SURFACE    SELECT ... END
                 VOLUME     MATRIX inte
                 DENSITY    CENTER ...
                 POTENTIAL

BOND 


...  BOND atom-num1 atom-num2 (atom-num3) -
          SELECT ... END
          ANGLE real

The SELECTED atom coordinates are ROTATED around the specified BOND for the specified ANGLE. It is not necessary that atom-num1 and atom-num2 are connected by a covalent bond. When a third atom (atom-num3) is specified it doesn't have to be connected to atom-num2. When the third atom is omitted then the program looks for it in the connection table for a neighbour of atom-num2. The default atom SELECTION is the group of atoms that are on the side of the atom-num2 of the covalent bond atom-num1 atom-num2 (SELECT CUT atom-num1 atom-num2 END ).

ATOM 


... ATOM  SELECT ... END
          MATRIX inte
          RMS
          CENTER ATOM atom-num
                 COORDINATE  3*real
                 CALCULATED

ROTATES the SELECTED atoms around the specified CENTER by multiplying atomic coordinates with the specified rotational MATRIX. The ROTATIONAL MATRICES can be specified by the SET MATRIX int ... command sentence. There are 8 matrices available. Using RMS the last RMS fit parameters are used to create the ROTATIONAL MATRIX. The default CENTER for the transformation is the coordinate system origin. Other CENTER positions can be chosen (the current image center - CALCULATED, an ATOM position or some other point in space - COORDINATES ).

POINTS 


... POINTS   SURFACE    SELECT ... END
             VOLUME     MATRIX inte
             DENSITY    RMS
             POTENTIAL  CENTER ...

Work on the same way as the ROTATE ATOM command with the only difference, that the points can be selected also by their kind (SURFACE, VOLUME, POTENTIAL, DENSITY).

Examples 


MAIN> rotate bond 3 4 angle 30.



MAIN> rotate atom select segment number 3 end -
MAIN> matrix 3 center atom 4



MAIN> rotate points potential select number segment 4 end -
MAIN> rms center calculated