“zoom” scales and translates the window and the origin to cover the atom selection.
zoom [ selection [, buffer [, state [, complete [, animate ]]]]]
selection = string: selection-expression or name pattern {default: all}
buffer = float: distance {default: 0}
state = 0: uses all coordinate states {default}
state = -1: uses only coordinates for the current state
state > 0: uses coordinates for a specific state
complete = 0 or 1: will insure no atoms centers are clipped
animate < 0: uses the default animation duration
animate = 0: no animation
animate > 0: animates using the provided duration in seconds
zoom zoom complete=1 zoom 142/, animate=3 zoom (chain A)
The zoom command normally tries to guess an optimal zoom level for visualization, balancing closeness against occasional clipping of atoms out of the field of view. You can change this behavior by setting the complete option to 1, which will guarantee that the atom positions for the entire selection will fit in the field of an orthoscopic view.
To absolutely prevent clipping, you may also need to add an additional buffer (typically 2 A) to account for graphical representations which extend beyond the atom coordinates.