Added vmd dipole moment update script for trajectories

scripts/vmd-dipole.tcl

@@ -0,0 +1,44 @@
+# Script to draw dipole moment vectors for resid's
+# and update for every frame in the tracjectory.
+# Dipole moment based on the geometric center.
+# Mikael Lund, September 2009.
+#
+# Usage:
+# Specify resid range in for-loop below.
+# $ source dipol.tcl
+# $ enabletrace
+
+proc vmd_draw_arrow {mol start end} {
+  set end [vecadd $start [vecscale 0.4 $end]]
+  set middle [vecadd $start [vecscale 0.8 [vecsub $end $start]]]
+  set start [vecadd $start [vecscale -0.9 [vecsub $end $start]]]
+  graphics $mol cylinder $start $middle radius 1.4
+  #graphics $mol cylinder $start $end radius 1.4
+  graphics $mol cone $middle $end radius 2.2
+}
+
+proc dipmom {args} {
+  graphics 0 delete all
+  for { set i 1 } { $i <= 1 } { incr i } {
+    set sel1 [atomselect top "resid $i"]
+    set muvec [measure dipole $sel1]
+    set cm [measure center $sel1]
+    #set vec [veclength $muvec]
+    graphics 0 color red
+    vmd_draw_arrow top $cm $muvec
+  }
+}
+
+proc enabletrace {} {
+  global vmd_frame
+  #trace add variable ::vmd_frame([molinfo top]) write dipmom
+  trace variable vmd_frame([molinfo top]) w dipmom
+}
+
+proc disabletrace {} {
+  global vmd_frame
+  #trace remove variable ::vmd_frame([molinfo top]) write dipmom
+  trace vdelete vmd_frame([molinfo top]) w dipmom
+}
+
+