diff --git a/gcoder.py b/gcoder.py
index 24f43b8..78a22fc 100755
--- a/gcoder.py
+++ b/gcoder.py
@@ -19,7 +19,7 @@ import re
 import math
 import datetime
 
-gcode_parsed_args = ["x", "y", "e", "f", "z", "p"]
+gcode_parsed_args = ["x", "y", "e", "f", "z", "p", "i", "j"]
 
 class Line(object):
 
@@ -28,6 +28,8 @@ class Line(object):
     z = None
     e = None
     f = None
+    i = None
+    j = None
     
     relative = False
     relative_e = False
@@ -263,7 +265,6 @@ class GCode(object):
         #TODO:
         # get device caps from firmware: max speed, acceleration/axis (including extruder)
         # calculate the maximum move duration accounting for above ;)
-        # self.log(".... estimating ....")
         zs = self.layers.keys()
         zs.sort()
         for z in zs:
@@ -281,7 +282,7 @@ class GCode(object):
                     x = line.x if line.x != None else lastx
                     y = line.y if line.y != None else lasty
                     e = line.e if line.e != None else laste
-                    f = line.f / 60.0 if line.f != None else lastf # mm/s vs mm/m
+                    f = line.f / 60.0 if line.f != None else lastf # mm/s vs mm/m => divide by 60
                     
                     # given last feedrate and current feedrate calculate the distance needed to achieve current feedrate.
                     # if travel is longer than req'd distance, then subtract distance to achieve full speed, and add the time it took to get there.
diff --git a/printrun/gviz.py b/printrun/gviz.py
index 9086b9e..334c5f5 100755
--- a/printrun/gviz.py
+++ b/printrun/gviz.py
@@ -312,10 +312,70 @@ class gviz(wx.Panel):
         dc.DrawBitmap(self.blitmap, 0, 0)
         del dc
 
-    def addfile(self, gcodes = []):
+    def addfile(self, gcode):
         self.clear()
-        for i in gcodes:
-            self.addgcode(i)
+        self.add_parsed_gcodes(gcode.lines)
+
+    def add_parsed_gcodes(self, lines, hilight = 0):
+        def _readgcode():
+            target = self.lastpos[:]
+            target[5] = 0.0
+            target[6] = 0.0
+            if hilight:
+                target = self.hilightpos[:]
+            if gline.x != None: target[0] = gline.x
+            if gline.y != None: target[1] = gline.y
+            if gline.z != None: target[2] = gline.z
+            if gline.e != None: target[3] = gline.e
+            if gline.f != None: target[4] = gline.f
+            if gline.i != None: target[5] = gline.i
+            if gline.j != None: target[6] = gline.j
+            if not hilight:
+                if not target[2] in self.lines.keys():
+                    self.lines[target[2]]=[]
+                    self.pens[target[2]]=[]
+                    self.arcs[target[2]]=[]
+                    self.arcpens[target[2]]=[]
+                    self.layers+=[target[2]]
+            return target
+
+        def _y(y):
+            return self.build_dimensions[1] - (y - self.build_dimensions[4])
+        def _x(x):
+            return x - self.build_dimensions[3]
+
+        for gline in lines:
+            start_pos = self.hilightpos[:] if hilight else self.lastpos[:]
+
+            if gline.command in [ "G0", "G1" ]:
+                target = _readgcode()
+                line = [ _x(start_pos[0]), _y(start_pos[1]), _x(target[0]), _y(target[1]) ]
+                if not hilight:
+                    self.lines[ target[2] ] += [line]
+                    self.pens[ target[2] ]  += [self.mainpen if target[3] != self.lastpos[3] else self.travelpen]
+                    self.lastpos = target
+                else:
+                    self.hilight += [line]
+                    self.hilightpos = target
+                self.dirty = 1
+
+            if gline.command in [ "G2", "G3" ]:
+                target = _readgcode()
+                arc = []
+                arc += [ _x(start_pos[0]), _y(start_pos[1]) ]
+                arc += [ _x(target[0]), _y(target[1]) ]
+                arc += [ _x(start_pos[0] + target[5]), _y(start_pos[1] + target[6]) ]  # center
+                if gline.command == "G2":  # clockwise, reverse endpoints
+                    arc[0], arc[1], arc[2], arc[3] = arc[2], arc[3], arc[0], arc[1]
+
+                if not hilight:
+                    self.arcs[ target[2] ]    += [arc]
+                    self.arcpens[ target[2] ] += [self.arcpen]
+                    self.lastpos = target
+                else:
+                    self.hilightarcs += [arc]
+                    self.hilightpos = target
+                self.dirty = 1
 
     def addgcode(self, gcode = "M105", hilight = 0):
         gcode = gcode.split("*")[0]