source: utils/developer/tcl/convexizing.tcl

#!/usr/bin/tclsh
#
# This scripts parses a series of tecplot style files of triangles and displays them via VMD's graphics interface

# fname is the filename prefix of the tecplot .dat files, e.g. "convex" for "convex-0.dat"
proc convexizing { fname steps} {
        global framesteps
        global fileprefix
        set framesteps $steps
        set fileprefix $fname

        # avoid some 'animate dup' bug
        set molid [molinfo top]
        if {$steps < 2} {
                error "steps should be greater than 2."
        }
        # make tcount-1 copies of current frame
        for {set i 0} {$i <$steps} {incr i} {
                animate dup frame 0 $molid
        }
        animate goto 0

        global vmd_frame
        trace variable vmd_frame([molinfo top]) w update_current_surface
        display update
        return
}       

proc update_current_surface {name index op} { 
        global fileprefix

        draw delete all
        set frame [molinfo $index get frame]
        # open file
        set fname "$fileprefix-$frame.dat"
        #puts "Opening new file $fname."
        set file [open $fname r]
        gets $file title
        gets $file variables
        gets $file zone
        # parse nodes
        set ncount 1
        gets $file line
        while { $line != {} } {
                set nodes($ncount) $line
                incr ncount
                gets $file line
        }
        set ncount [ expr $ncount -1 ]
        # there's a blank line in between
        # parse triangles
        set tcount 0
        gets $file line
        while { $line != {} } {
                set triangles [ split $line " "]
                set first [ lrange $nodes([ lindex $triangles 0 ]) 0 2 ]
                set second [ lrange $nodes([ lindex $triangles 1 ]) 0 2 ]
                set third [ lrange $nodes([ lindex $triangles 2 ]) 0 2 ]
                draw color blue
                draw material Transparent
                draw triangle $first $second $third
                incr tcount
                gets $file line
        }
        close $file
        #puts "There are $tcount triangles."
        
        return
}

proc convexizing_off {} {
        global vmd_frame
        global framesteps
        trace vdelete vmd_frame([molinfo top]) w update_current_surface
        draw delete all
        animate delete beg 1 end $framesteps skip 0 [molinfo top]
        return
}