Rotation and Translation


xy-Rotation: press the left mouse button, and move the mouse. This causes the molecule to rotate around an axis which is parallel to the screen ("xy"-plane) and orthogonal to the direction of the movement of the mouse. The rotation axis passes through the "pivot" of rotation, which originally coincides with the origin of the coordinate system.

or

Wit!P> display rotate / x 37.25
Wit!P> display rotate / y 121.5
to rotate around x-axis (y-axis) by given angle (degrees).


xy-Translation: press the middle mouse button, and move the mouse. The molecule will be "follow" the mouse.

or

Wit!P> display translate / 12.5 0.0 -5.2
to translate by (dx,dy,dz) = (12.5, 0.0, -5.2) Å.

z-Rotation: simultaneously press the left&right mouse buttons and move the mouse. The molecule will be rotated around an axis of rotation parallel to the the z-axis and through the "pivot" of rotation. The angle of rotation is equal to the angle between the initial mouse position, the center of the screen, and the final mouse position. (This implies a singularity of rotation at the screen center, in the neighborhood of which z-rotation can be an unpleasant experience...).

or

Wit!P> display rotate / z 90.0
to rotate around z by 90 degrees.

z-Translation: to translate the molecule, press the middle&right mouse buttons and move the mouse up (translation "into" the screen) or down (translation "out of" the screen). If the viewing mode is perspective (which is the default), z-translation will lead to an apparent change of scale, which sometimes surprises users which are not accustomed to perspective viewing. Please try not to confuse the mouse LM (left&middle buttons = scale) and MR (middle&right buttons = z-translation).


The next section will introduce you to the Molecular Data Tree.



A.Widmer, NIBR/CPC/CSG-SB