Draw objects centered on the offset position in plater

plater.py

@@ -327,10 +327,9 @@ class StlPlater(Plater):
                     maxz = j[2]
         model.dims = [minx, maxx, miny, maxy, minz, maxz]
         self.add_model(name, model)
-        #if minx < 0:
-        #    model.offsets[0] = -minx
-        #if miny < 0:
-        #    model.offsets[1] = -miny
+        model.centeroffset = [(maxx - minx) / 2,
+                              (maxy - miny) / 2,
+                              0]
         self.s.drawmodel(model, 2)
 
     def export_to(self, name):

printrun/stlview.py

@@ -354,12 +354,14 @@ class StlViewPanel(wxGLPanel):
         glPushMatrix()
 
         # Draw objects
-        for i in self.parent.models.values():
+        for i in self.parent.models:
+            model = self.parent.models[i]
             glPushMatrix()
-            glTranslatef(*(i.offsets))
-            glRotatef(i.rot, 0.0, 0.0, 1.0)
-            glScalef(*i.scale)
-            i.batch.draw()
+            glTranslatef(*(model.offsets))
+            glTranslatef(*(model.centeroffset))
+            glRotatef(model.rot, 0.0, 0.0, 1.0)
+            glScalef(*model.scale)
+            model.batch.draw()
             glPopMatrix()
         glPopMatrix()
         glPopMatrix()