[Bf-extensions-cvs] [0f2f0e4] master: Fix T47490: STL: faces not normalized correctly when exporting multiple meshes.

[Bastien Montagne]

Commit: 0f2f0e49517612db379f7f2958b1d1967e7e9e19
Author: Bastien Montagne
Date:   Sun Feb 28 16:48:08 2016 +0100
Branches: master
https://developer.blender.org/rBA0f2f0e49517612db379f7f2958b1d1967e7e9e19

Fix T47490: STL: faces not normalized correctly when exporting multiple meshes.

Using new `mesh.flip_normals()` when the mesh is transformed with a negative matrix (mirror along one axis e.g.).

===================================================================

M	io_mesh_stl/blender_utils.py

===================================================================

diff --git a/io_mesh_stl/blender_utils.py b/io_mesh_stl/blender_utils.py
index a5492d0..864335a 100644
--- a/io_mesh_stl/blender_utils.py
+++ b/io_mesh_stl/blender_utils.py
@@ -88,7 +88,11 @@ def faces_from_mesh(ob, global_matrix, use_mesh_modifiers=False, triangulate=Tru
     except RuntimeError:
         raise StopIteration
 
-    mesh.transform(global_matrix * ob.matrix_world)
+    mat = global_matrix * ob.matrix_world
+    mesh.transform(mat)
+    if mat.is_negative:
+        mesh.flip_normals()
+        mesh.calc_tessface()
 
     if triangulate:
         # From a list of faces, return the face triangulated if needed.