fixed the order of vertices when exporting a model to an STL file

disabled code for adding comments to the STL files
fixed two sample STL files with wrong order of vertices


git-svn-id: https://pycam.svn.sourceforge.net/svnroot/pycam/trunk@718 bbaffbd6-741e-11dd-a85d-61de82d9cad9

samples/Box2.stl

-solid "model"; Produced by pycam, 2010-09-23
-;PYCAM-META-DATA: Filename: samples/Box2.stl
-;PYCAM-META-DATA: Timestamp: 2010-09-23 20:22:11.660612
-;PYCAM-META-DATA: Version: 0.3
+solid "model"; Produced by pycam (v0.3), 2010-10-03
 facet normal 0.707143 -0.408041 0.577452
   outer loop
-    vertex 2.563112 -5.599983 2.267282
-    vertex 2.562797 -2.393577 4.533387
     vertex 5.339321 -3.997340 0.000022
+    vertex 2.562797 -2.393577 4.533387
+    vertex 2.563112 -5.599983 2.267282
   endloop
 endfacet
 facet normal 0.707143 -0.408041 0.577452
   outer loop
-    vertex 5.339321 -3.997340 0.000022
-    vertex 2.562797 -2.393577 4.533387
     vertex 5.339006 -0.790934 2.266127
+    vertex 2.562797 -2.393577 4.533387
+    vertex 5.339321 -3.997340 0.000022
   endloop
 endfacet
 facet normal -0.707143 0.408041 -0.577452
   outer loop
-    vertex -0.213384 -3.997869 0.000000
-    vertex 2.562824 -2.395226 -2.267260
     vertex -0.213699 -0.791464 2.266105
+    vertex 2.562824 -2.395226 -2.267260
+    vertex -0.213384 -3.997869 0.000000
   endloop
 endfacet
 facet normal -0.707143 0.408041 -0.577452
   outer loop
-    vertex -0.213699 -0.791464 2.266105
-    vertex 2.562824 -2.395226 -2.267260
     vertex 2.562510 0.811179 -0.001155
+    vertex 2.562824 -2.395226 -2.267260
+    vertex -0.213699 -0.791464 2.266105
   endloop
 endfacet
 facet normal 0.707070 0.408176 -0.577446
   outer loop
-    vertex 5.339006 -0.790934 2.266127
-    vertex 2.562510 0.811179 -0.001155
     vertex 2.562824 -2.395226 -2.267260
+    vertex 2.562510 0.811179 -0.001155
+    vertex 5.339006 -0.790934 2.266127
   endloop
 endfacet
 facet normal 0.707070 0.408176 -0.577446
   outer loop
-    vertex 5.339006 -0.790934 2.266127
-    vertex 2.562824 -2.395226 -2.267260
     vertex 5.339321 -3.997340 0.000022
+    vertex 2.562824 -2.395226 -2.267260
+    vertex 5.339006 -0.790934 2.266127
   endloop
 endfacet
 facet normal -0.707070 -0.408176 0.577446
   outer loop
-    vertex -0.213384 -3.997869 0.000000
-    vertex -0.213699 -0.791464 2.266105
     vertex 2.562797 -2.393577 4.533387
+    vertex -0.213699 -0.791464 2.266105
+    vertex -0.213384 -3.997869 0.000000
   endloop
 endfacet
 facet normal -0.707070 -0.408176 0.577446
   outer loop
-    vertex -0.213384 -3.997869 0.000000
-    vertex 2.562797 -2.393577 4.533387
     vertex 2.563112 -5.599983 2.267282
+    vertex 2.562797 -2.393577 4.533387
+    vertex -0.213384 -3.997869 0.000000
   endloop
 endfacet
 facet normal -0.000080 0.816637 0.577152
   outer loop
-    vertex -0.213699 -0.791464 2.266105
-    vertex 2.562510 0.811179 -0.001155
     vertex 5.339006 -0.790934 2.266127
+    vertex 2.562510 0.811179 -0.001155
+    vertex -0.213699 -0.791464 2.266105
   endloop
 endfacet
 facet normal -0.000080 0.816637 0.577152
   outer loop
-    vertex -0.213699 -0.791464 2.266105
-    vertex 5.339006 -0.790934 2.266127
     vertex 2.562797 -2.393577 4.533387
+    vertex 5.339006 -0.790934 2.266127
+    vertex -0.213699 -0.791464 2.266105
   endloop
 endfacet
 facet normal 0.000080 -0.816637 -0.577152
   outer loop
-    vertex -0.213384 -3.997869 0.000000
-    vertex 2.563112 -5.599983 2.267282
     vertex 5.339321 -3.997340 0.000022
+    vertex 2.563112 -5.599983 2.267282
+    vertex -0.213384 -3.997869 0.000000
   endloop
 endfacet
 facet normal 0.000080 -0.816637 -0.577152
   outer loop
-    vertex -0.213384 -3.997869 0.000000
-    vertex 5.339321 -3.997340 0.000022
     vertex 2.562824 -2.395226 -2.267260
+    vertex 5.339321 -3.997340 0.000022
+    vertex -0.213384 -3.997869 0.000000
   endloop
 endfacet
 endsolid

src/pycam/Exporters/STLExporter.py

@@ -21,6 +21,7 @@ You should have received a copy of the GNU General Public License
 along with PyCAM.  If not, see <http://www.gnu.org/licenses/>.
 """
 
+from pycam import VERSION
 import datetime
 import os
 
@@ -46,15 +47,21 @@ class STLExporter:
 
     def get_output_lines(self):
         date = datetime.date.today().isoformat()
-        yield """solid "%s"; Produced by %s, %s""" % (self.name, self.created_by, date)
+        yield """solid "%s"; Produced by %s (v%s), %s""" \
+                % (self.name, self.created_by, VERSION, date)
+        # sadly STL does not seem to support comments
+        """
         if self.comment:
             for line in self.comment.split(self.linesep):
                 yield(";%s" % line)
+        """
         for tr in self.model.triangles():
             norm = tr.normal.normalized()
             yield "facet normal %f %f %f" % (norm.x, norm.y, norm.z)
             yield "  outer loop"
-            for p in (tr.p1, tr.p2, tr.p3):
+            # Triangle vertices are stored in clockwise order - thus we need
+            # to reverse the order (STL expects counter-clockwise orientation).
+            for p in (tr.p3, tr.p2, tr.p1):
                 yield "    vertex %f %f %f" % (p.x, p.y, p.z)
             yield "  endloop"
             yield "endfacet"