Kimkulling/fix pyassimp compatibility (#5563)

* Use correct exception message access

* Add missing docs

code/Geometry/GeometryUtils.h

@@ -49,6 +49,10 @@ namespace Assimp {
 // ---------------------------------------------------------------------------
 class ASSIMP_API GeometryUtils {
 public:
+    /// @brief Will calculate the area of a triangle.
+    /// @param a  The first vertex of the triangle.
+    /// @param b  The first vertex of the triangle.
+    /// @param c  The first vertex of the triangle.
     static ai_real heron( ai_real a, ai_real b, ai_real c );
     
     /// @brief Will compute the distance between 2 3D-vectors

port/PyAssimp/scripts/3d_viewer.py

@@ -466,8 +466,8 @@ class PyAssimp3DViewer:
         try:
             self.set_shaders_v130()
             self.prepare_shaders()
-        except RuntimeError, message:
-            sys.stderr.write("%s\n" % message)
+        except RuntimeError as e:
+            sys.stderr.write("%s\n" % e.message)
             sys.stdout.write("Could not compile shaders in version 1.30, trying version 1.20\n")
 
         if not shader_compilation_succeeded: