diff --git a/gviz.py b/gviz.py
index 9bdfa65..0d12c4d 100755
--- a/gviz.py
+++ b/gviz.py
@@ -1,9 +1,9 @@
 import wx,time
 
 class window(wx.Frame):
-    def __init__(self,f,size=(600,600),bedsize=(200,200),grid=(10,50)):
+    def __init__(self,f,size=(600,600),bedsize=(200,200),grid=(10,50),extrusion_width=0.5):
         wx.Frame.__init__(self,None,title="Layer view (Use shift+mousewheel to switch layers)",size=(size[0],size[1]))
-        self.p=gviz(self,size=size,bedsize=bedsize,grid=grid)
+        self.p=gviz(self,size=size,bedsize=bedsize,grid=grid,extrusion_width=extrusion_width)
         s=time.time()
         for i in f:
             self.p.addgcode(i)
@@ -53,7 +53,7 @@ class window(wx.Frame):
             elif z < 0: self.p.zoom(event.GetX(),event.GetY(),1/1.2)
         
 class gviz(wx.Panel):
-    def __init__(self,parent,size=(200,200),bedsize=(200,200),grid=(10,50)):
+    def __init__(self,parent,size=(200,200),bedsize=(200,200),grid=(10,50),extrusion_width=0.5):
         wx.Panel.__init__(self,parent,-1,size=(size[0],size[1]))
         self.size=size
         self.bedsize=bedsize
@@ -66,7 +66,7 @@ class gviz(wx.Panel):
         self.pens={}
         self.layers=[]
         self.layerindex=0
-        self.filament_width=0.5 # set it to 0 to disable scaling lines with zoom
+        self.filament_width=extrusion_width # set it to 0 to disable scaling lines with zoom
         self.scale=[min(float(size[0])/bedsize[0],float(size[1])/bedsize[1])]*2
         penwidth = max(1.0,self.filament_width*((self.scale[0]+self.scale[1])/2.0))
         self.translate=[0.0,0.0]
diff --git a/pronterface.py b/pronterface.py
index 5aae840..25e004a 100755
--- a/pronterface.py
+++ b/pronterface.py
@@ -49,6 +49,7 @@ class PronterWindow(wx.Frame,pronsole.pronsole):
         self.settings.bed_size_y = 200.
         self.settings.preview_grid_step1 = 10.
         self.settings.preview_grid_step2 = 50.
+        self.settings.preview_extrusion_width = 0.5
         self.filename=filename
         os.putenv("UBUNTU_MENUPROXY","0")
         wx.Frame.__init__(self,None,title="Printer Interface",size=size);
@@ -515,11 +516,13 @@ class PronterWindow(wx.Frame,pronsole.pronsole):
         lls.Add((10,0),pos=(0,11),span=(1,1))
         self.gviz=gviz.gviz(self.panel,(300,300),
             bedsize=(self.settings.bed_size_x,self.settings.bed_size_y),
-            grid=(self.settings.preview_grid_step1,self.settings.preview_grid_step2))
+            grid=(self.settings.preview_grid_step1,self.settings.preview_grid_step2),
+            extrusion_width=self.settings.preview_extrusion_width)
         self.gviz.showall=1
         self.gwindow=gviz.window([],
             bedsize=(self.settings.bed_size_x,self.settings.bed_size_y),
-            grid=(self.settings.preview_grid_step1,self.settings.preview_grid_step2))
+            grid=(self.settings.preview_grid_step1,self.settings.preview_grid_step2),
+            extrusion_width=self.settings.preview_extrusion_width)
         self.gviz.Bind(wx.EVT_LEFT_DOWN,self.showwin)
         self.gwindow.Bind(wx.EVT_CLOSE,lambda x:self.gwindow.Hide())
         cs=self.centersizer=wx.GridBagSizer()