Collada Export Py3 Fixes

To allow successful Collada Export for Py3 and Py2, tested import of DAE file with colours from Blender to ensure no regression on the import side. Note: I had to download Pycollada to enable testing in Conda build.

src/Mod/Arch/importDAE.py

@@ -42,6 +42,12 @@ __url__ = "http://www.freecadweb.org"
 
 DEBUG = True
 
+try:
+    # Python 2 forward compatibility
+    range = xrange
+except NameError:
+    pass
+
 def checkCollada():
     "checks if collada if available"
     global collada
@@ -176,7 +182,10 @@ def export(exportList,filename,tessellation=1):
     colmesh.assetInfo.upaxis = collada.asset.UP_AXIS.Z_UP
     # authoring info
     cont = collada.asset.Contributor()
-    author = FreeCAD.ActiveDocument.CreatedBy.encode("utf8")
+    try:
+        author = FreeCAD.ActiveDocument.CreatedBy
+    except UnicodeEncodeError:
+        author = FreeCAD.ActiveDocument.CreatedBy.encode("utf8")
     author = author.replace("<","")
     author = author.replace(">","")
     cont.author = author
@@ -215,19 +224,19 @@ def export(exportList,filename,tessellation=1):
 
             # vertex indices
             vindex = numpy.empty(len(Topology[0]) * 3)
-            for i in xrange(len(Topology[0])):
+            for i in range(len(Topology[0])):
                 v = Topology[0][i]
                 vindex[list(range(i*3, i*3+3))] = (v.x*scale,v.y*scale,v.z*scale)
 
             # normals
             nindex = numpy.empty(len(Facets) * 3)
-            for i in xrange(len(Facets)):
+            for i in range(len(Facets)):
                 n = Facets[i].Normal
                 nindex[list(range(i*3, i*3+3))] = (n.x,n.y,n.z)
 
             # face indices
             findex = numpy.empty(len(Topology[1]) * 6, numpy.int64)
-            for i in xrange(len(Topology[1])):
+            for i in range(len(Topology[1])):
                 f = Topology[1][i]
                 findex[list(range(i*6, i*6+6))] = (f[0],i,f[1],i,f[2],i)