diff --git a/boxes/__init__.py b/boxes/__init__.py
index 353d98d..1498181 100755
--- a/boxes/__init__.py
+++ b/boxes/__init__.py
@@ -21,6 +21,7 @@ from argparse import ArgumentParser
 import re
 from functools import wraps
 from boxes import edges
+from boxes import svgutil
 
 ### Helpers
 
@@ -173,22 +174,18 @@ class Boxes:
             "--burn",  action="store", type=float, default=0.05,
             help="burn correction in mm")
 
-    def open(self, width, height):
+    def open(self):
         """
         Prepare for rendering
 
         Call this function from your .render() method
-
-        :param width: width of canvas in mm
-        :param height: height of canvas in mm
-
         """
         self.spacing = 2*self.burn + 0.5 * self.thickness
 
         self.fingerHoleEdgeWidth = 1.0    # multitudes of self.thickness
         self.bedBoltSettings = (3, 5.5, 2, 20, 15) #d, d_nut, h_nut, l, l1
         self.hexHolesSettings = (5, 3, 'circle') # r, dist, style
-        self._init_surface(width, height)
+        self._init_surface(1000, 1000)
         self._buildObjects()
 
     def buildArgParser(self, *l):
@@ -329,7 +326,7 @@ class Boxes:
         """Implement this method in your sub class.
 
         You will typically need to call .parseArgs() before calling this one"""
-        self.open(100, 100)
+        self.open()
         # Change settings and creat new Edges and part classes here
         raise NotImplemented
         self.close()
@@ -385,6 +382,11 @@ class Boxes:
         self.surface.flush()
         self.surface.finish()
 
+
+        svg = svgutil.SVGFile(self.output)
+        svg.getEnvelope()
+        svg.rewriteViewPort()
+        return
         f = open(self.output, "r+")
         s = f.read(1024)
         pos = s.find('pt"')
@@ -1111,7 +1113,7 @@ class DemoBox(Boxes):
     def render(self):
         """ """
         x, y, h, t = self.x, self.y, self.h, self.thickness
-        self.open(2*x+10*self.thickness, y+2*h+20*self.thickness)
+        self.open()
         self.ctx.save()
 
         self.moveTo(t, t)
diff --git a/boxes/generators/_template.py b/boxes/generators/_template.py
index 8fead5a..73e3d1a 100644
--- a/boxes/generators/_template.py
+++ b/boxes/generators/_template.py
@@ -32,8 +32,8 @@ class Box(Boxes):
         # adjust to the variables you want in the local scope
         x, y, h = self.x, self.y, self.h
         t = self.thickness
-        # Calculate canvas size and pass as width and height
-        self.open(width=x+y+40, height=y+2*h+50)
+        # Initialize canvas
+        self.open()
 
         # Change settings of default edges if needed. E.g.:
         self.edges["f"].settings.setValues(self.thickness, space=3, finger=3,
diff --git a/boxes/generators/box.py b/boxes/generators/box.py
index 8478a4c..208f093 100755
--- a/boxes/generators/box.py
+++ b/boxes/generators/box.py
@@ -29,7 +29,7 @@ class Box(Boxes):
     def render(self):
         x, y, h = self.x, self.y, self.h
         t = self.thickness
-        self.open(width=max(x+y,2*x)+10*t, height=y+2*h+12*t)
+        self.open()
 
         d2 = [edges.Bolts(2)]
         d3 = [edges.Bolts(3)]
diff --git a/boxes/generators/box2.py b/boxes/generators/box2.py
index 4a62214..8de63b9 100755
--- a/boxes/generators/box2.py
+++ b/boxes/generators/box2.py
@@ -32,7 +32,7 @@ class Box(Boxes):
     def render(self):
         x, y, h = self.x, self.y, self.h
 
-        self.open(width=x+y+40, height=y+2*h+50)
+        self.open()
 
         b = self.edges.get(self.bottom_edge, self.edges["F"])
         t = self.edges.get(self.top_edge, self.edges["e"])
diff --git a/boxes/generators/box3.py b/boxes/generators/box3.py
index 906d181..6e3e577 100755
--- a/boxes/generators/box3.py
+++ b/boxes/generators/box3.py
@@ -30,7 +30,7 @@ class Box(Boxes):
         x, y, h = self.x, self.y, self.h
         t = self.thickness
 
-        self.open(width=x+y+10*t, height=y+h+10*t)
+        self.open()
 
         d2 = [edges.Bolts(2)]
         d3 = [edges.Bolts(3)]
diff --git a/boxes/generators/castle.py b/boxes/generators/castle.py
index d960e51..c52045b 100755
--- a/boxes/generators/castle.py
+++ b/boxes/generators/castle.py
@@ -22,7 +22,7 @@ class Castle(Boxes):
         Boxes.__init__(self)
 
     def render(self, t_x=70, t_h=250, w1_x=300, w1_h=120, w2_x=100, w2_h=120):
-        self.open(800, 600)
+        self.open()
         s = edges.FingerJointSettings(self.thickness, relative=False,
                                       space = 10, finger=10, height=10,
                                       width=self.thickness)
diff --git a/boxes/generators/drillbox.py b/boxes/generators/drillbox.py
index 1368ac3..55d982d 100755
--- a/boxes/generators/drillbox.py
+++ b/boxes/generators/drillbox.py
@@ -53,7 +53,7 @@ in 0.5mm steps, 3 holes each size"""
         x, y, h = self.x, self.y, self.h
         t = self.thickness
 
-        self.open(width=x+y+40, height=3*y+2*h+16*t)
+        self.open()
         self.edges["f"].settings.setValues(self.thickness, space=3, finger=3,
                                 surroundingspaces=1)
 
diff --git a/boxes/generators/flexbox.py b/boxes/generators/flexbox.py
index 15bfb2c..22b4cc4 100755
--- a/boxes/generators/flexbox.py
+++ b/boxes/generators/flexbox.py
@@ -76,10 +76,7 @@ class FlexBox(boxes.Boxes):
         self.latchsize = 8 * self.thickness
         c4 = math.pi * r * 0.5
 
-        width = 2*x + 2*y - 8*r + 4*c4 + 4*self.thickness
-        height = y + h + 8*self.thickness
-
-        self.open(width, height)
+        self.open()
 
         self.moveTo(self.thickness, self.thickness)
         self.surroundingWall()
diff --git a/boxes/generators/flexbox2.py b/boxes/generators/flexbox2.py
index f7b8527..d14420e 100755
--- a/boxes/generators/flexbox2.py
+++ b/boxes/generators/flexbox2.py
@@ -71,10 +71,7 @@ class FlexBox(Boxes):
         self.c4 = c4 = math.pi * self.radius * 0.5
         self.latchsize = 8*self.thickness
 
-        width = 2*self.x + self.y - 3*self.radius + 2*c4 + 7*self.thickness + self.latchsize # lock
-        height = self.y + self.h + 8*self.thickness
-
-        self.open(width, height)
+        self.open()
 
         self.fingerJointSettings = (4, 4)
 
diff --git a/boxes/generators/flexbox3.py b/boxes/generators/flexbox3.py
index c25b80f..6b2d47d 100755
--- a/boxes/generators/flexbox3.py
+++ b/boxes/generators/flexbox3.py
@@ -109,7 +109,7 @@ class FlexBox(Boxes):
         width = 2*x + y - 2*r + c4 + 14*thickness + 3*h # lock
         height = y + z + 8*thickness
 
-        self.open(width, height)
+        self.open()
 
         self.edges["f"].settings.setValues(
             self.thickness, finger=2, space=2, surroundingspaces=1)
diff --git a/boxes/generators/flextest.py b/boxes/generators/flextest.py
index f4647e4..fbc5c0e 100755
--- a/boxes/generators/flextest.py
+++ b/boxes/generators/flextest.py
@@ -33,7 +33,7 @@ class FlexTest(Boxes):
 
     def render(self):
         x, y = self.x, self.y
-        self.open(x+60, y+20)
+        self.open()
 
         self.edges["X"].settings.setValues(
             self.thickness, relative=True,
diff --git a/boxes/generators/folder.py b/boxes/generators/folder.py
index 8b14e3b..5e1cd3a 100755
--- a/boxes/generators/folder.py
+++ b/boxes/generators/folder.py
@@ -31,7 +31,7 @@ class Folder(Boxes):
     def render(self):
         x, y, r, h = self.x, self.y, self.r, self.h
         c2 = math.pi * h
-        self.open(width=2*x+3*h+20, height=y+20)
+        self.open()
         self.moveTo(r+self.thickness, self.thickness)
         self.edge(x-r)
         self.edges["X"](c2, y)
diff --git a/boxes/generators/lamp.py b/boxes/generators/lamp.py
index 8cf58da..12ac1c6 100755
--- a/boxes/generators/lamp.py
+++ b/boxes/generators/lamp.py
@@ -77,7 +77,7 @@ class Lamp(Boxes):
         h : height box
         """
 
-        self.open(width=1000, height=1000)
+        self.open()
 
         #self.edges["f"].settings = (5, 5) # XXX
 
diff --git a/boxes/generators/magazinefile.py b/boxes/generators/magazinefile.py
index ad139c0..86c2bf6 100755
--- a/boxes/generators/magazinefile.py
+++ b/boxes/generators/magazinefile.py
@@ -64,7 +64,7 @@ class Box(Boxes):
         self.hi = hi = self.hi or (h / 2.0)
         t = self.thickness
 
-        self.open(width=x+y+8*t, height=x+h+hi+4*t)
+        self.open()
 
         self.ctx.save()
         self.rectangularWall(x, h, "Ffef", move="up")
diff --git a/boxes/generators/printer.py b/boxes/generators/printer.py
index 1a7fa6c..a98206e 100755
--- a/boxes/generators/printer.py
+++ b/boxes/generators/printer.py
@@ -121,7 +121,7 @@ class Printer(Boxes):
         self.move(overallwidth, overallheight, move)
 
     def render(self):
-        self.open(650, 600)
+        self.open()
         self.edges["f"].settings.setValues(self.thickness, surroundingspaces=0)
         self.ctx.save()
         for i in range(3):
diff --git a/boxes/generators/silverwarebox.py b/boxes/generators/silverwarebox.py
index 5ecbdd4..1fb6ceb 100755
--- a/boxes/generators/silverwarebox.py
+++ b/boxes/generators/silverwarebox.py
@@ -70,7 +70,7 @@ using flex for rounded corners"""
 
     def render(self):
         x, y, h, r = 250, 250/1.618, 120, 30
-        self.open(750, 450)
+        self.open()
         t = self.thickness
         b = self.burn
 
diff --git a/boxes/generators/trayinsert.py b/boxes/generators/trayinsert.py
index fa177a9..5350c78 100755
--- a/boxes/generators/trayinsert.py
+++ b/boxes/generators/trayinsert.py
@@ -28,8 +28,7 @@ class TrayInsert(Boxes):
         h = self.h
         t = self.thickness
 
-        self.open(width=max(x, y) + 4*t,
-                  height=(len(self.sx)+len(self.sy)-2)*(h+t)+2*t)
+        self.open()
         self.moveTo(t, t)
 
         # Inner walls
diff --git a/boxes/generators/traylayout.py b/boxes/generators/traylayout.py
index 5f18e9c..5cb578a 100755
--- a/boxes/generators/traylayout.py
+++ b/boxes/generators/traylayout.py
@@ -105,8 +105,7 @@ class Layout(Boxes):
             for f in line:
                 hasfloor |= f
 
-        self.open(max((lx+1)*sum(self.y), (ly+1)*sum(self.x))+lx*ly*4*t,
-                  2*self.h + hasfloor*sum(self.y) + 12*t)
+        self.open()
 
         self.edges["s"] = boxes.edges.Slot(self, self.hi/2.0)
         self.edges["C"] = boxes.edges.CrossingFingerHoleEdge(self, self.hi)
diff --git a/boxes/generators/typetray.py b/boxes/generators/typetray.py
index 93c5f09..af22f67 100755
--- a/boxes/generators/typetray.py
+++ b/boxes/generators/typetray.py
@@ -78,7 +78,7 @@ class TypeTray(Boxes):
         hi = self.hi = self.hi or h
         t = self.thickness
 
-        self.open(width=2*max(x,y)+10*t, height=(len(self.sx)+len(self.sy))*(h+2*t)+4*t)
+        self.open()
 
         self.moveTo(t, t)
         # outer walls