Environment

     The Environment check boxes are used to determine which frames of reference, if any, are to appear in the model display.

     If the Show Virtual Sphere check box is checked, the virtual sphere is included in the model display.  If the check box is unchecked, the sphere is not included.  Since a model is rotated by clicking somewhere relative to the virtual sphere, it will often be useful to include the  sphere.

     If the Show xyz-Axes check box is checked, the xyz-axes are included in the model display.  If the check box is unchecked, the axes are not included.  It may be helpful to include the axes when the shape of the molecule is complicated and/or while rotations are being performed.  Note:  The z-axis is perpendicular to the x and y axes (and to the screen), and so the axis appears as a point at their intersection.