Trajectory Path 1.2
-------------------

REQUIREMENTS: VMD Version 1.8 or greater

DESCRIPTION:
	For each step in the animation, the center of mass of the selection is
	calculated.  A new graphics molecule is created containing lines connected
	successive coordinates.  The color is a solid color (default is blue) or
	they are mapped to the color scale from lowest (= first trajectory frame)
	to highest (= last trajectory frame).


PROCEDURES:
	trajectory_path selection {color blue} {linewidth 1} {update 0}

        follows the center of mass of the given selection.  
        'color' is a solid color, or "scale" for color scale.
        'linewidth' is the width of the line drawn.
        'update' toggles calling "$selection update"

EXAMPLE USAGE:
	# Choose a selection
	set water [atomselect top "resid 5243"]
	# and then trace out its trajectory over time
	trajectory_path $water scale

        # follow the solvation shell around an atom.
        set solv  [atomselect top "water and exwithin 3.8 of index 199"]
        trajectory_path $solv yellow 3 1

EXAMPLE OUTPUT:
	Example 
        comparing the Grotthuss-diffusion of a hydronium ion (yellow) to
        the movements of individual protons (other colors) over the
        course of a Car-Parrinello MD-simulation.

DOWNLOAD FILE:
	trajectory_path.tcl

AUTHORS:
	Andrew Dalke (dalke@ks.uiuc.edu)
        Axel Kohlmeyer (akohlmey@cmm.chem.upenn.edu) (linewidth/update flag)