3 files changed, 38 insertions, 13 deletions

diff --git a/source/blender/render/intern/include/renderdatabase.h b/source/blender/render/intern/include/renderdatabase.h
index 9b14560b5f5..da45a2bfead 100644
--- a/source/blender/render/intern/include/renderdatabase.h
+++ b/source/blender/render/intern/include/renderdatabase.h
@@ -33,6 +33,10 @@
 #ifndef __RENDERDATABASE_H__
 #define __RENDERDATABASE_H__
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct Object;
 struct VlakRen;
 struct VertRen;
@@ -159,6 +163,9 @@ void area_lamp_vectors(struct LampRen *lar);
 void init_render_world(Render *re);
 void RE_Database_FromScene_Vectors(Render *re, struct Main *bmain, struct Scene *sce, unsigned int lay);
 
+#ifdef __cplusplus
+}
+#endif
 
 #endif /* __RENDERDATABASE_H__ */
 
diff --git a/source/blender/render/intern/raytrace/rayobject.cpp b/source/blender/render/intern/raytrace/rayobject.cpp
index 9e639501fdd..1ef44bbdd17 100644
--- a/source/blender/render/intern/raytrace/rayobject.cpp
+++ b/source/blender/render/intern/raytrace/rayobject.cpp
@@ -43,6 +43,7 @@
 #include "rayobject.h"
 #include "raycounter.h"
 #include "render_types.h"
+#include "renderdatabase.h"
 
 /* RayFace
  *
@@ -326,15 +327,33 @@ MALWAYS_INLINE int intersect_rayface(RayObject *hit_obj, RayFace *face, Isect *i
 			if (dist < 0.1f && is->orig.ob == face->ob) {
 				VlakRen *a = (VlakRen *)is->orig.face;
 				VlakRen *b = (VlakRen *)face->face;
+				ObjectRen *obr = ((ObjectInstanceRen *)face->ob)->obr;
+
+				VertRen **va, **vb;
+				int *org_idx_a, *org_idx_b;
+				int i, j;
+				bool is_neighbor = false;
+
+				/* "same" vertex means either the actual same VertRen, or the same 'final org index', if available
+				 * (autosmooth only, currently). */
+				for (i = 0, va = &a->v1; !is_neighbor && i < 4 && *va; ++i, ++va) {
+					org_idx_a = RE_vertren_get_origindex(obr, *va, false);
+					for (j = 0, vb = &b->v1; !is_neighbor && j < 4 && *vb; ++j, ++vb) {
+						if (*va == *vb) {
+							is_neighbor = true;
+						}
+						else if (org_idx_a) {
+							org_idx_b = RE_vertren_get_origindex(obr, *vb, 0);
+							if (org_idx_b && *org_idx_a == *org_idx_b) {
+								is_neighbor = true;
+							}
+						}
+					}
+				}
 
-				/* so there's a shared edge or vertex, let's intersect ray with
-				 * face itself, if that's true we can safely return 1, otherwise
-				 * we assume the intersection is invalid, 0 */
-				if (a->v1 == b->v1 || a->v2 == b->v1 || a->v3 == b->v1 || a->v4 == b->v1 ||
-				    a->v1 == b->v2 || a->v2 == b->v2 || a->v3 == b->v2 || a->v4 == b->v2 ||
-				    a->v1 == b->v3 || a->v2 == b->v3 || a->v3 == b->v3 || a->v4 == b->v3 ||
-				    (b->v4 && (a->v1 == b->v4 || a->v2 == b->v4 || a->v3 == b->v4 || a->v4 == b->v4)))
-				{
+				/* So there's a shared edge or vertex, let's intersect ray with self, if that's true
+				 * we can safely return 1, otherwise we assume the intersection is invalid, 0 */
+				if (is_neighbor) {
 					/* create RayFace from original face, transformed if necessary */
 					RayFace origface;
 					ObjectInstanceRen *ob = (ObjectInstanceRen *)is->orig.ob;
diff --git a/source/blender/render/intern/source/convertblender.c b/source/blender/render/intern/source/convertblender.c
index a9e2e1c2daf..908215f4215 100644
--- a/source/blender/render/intern/source/convertblender.c
+++ b/source/blender/render/intern/source/convertblender.c
@@ -3188,10 +3188,6 @@ static void init_render_mesh(Render *re, ObjectRen *obr, int timeoffset)
 		}
 		need_nmap_tangent= 1;
 	}
-	
-	/* origindex currently only used when baking to vertex colors */
-	if (re->flag & R_BAKING && re->r.bake_flag & R_BAKE_VCOL)
-		need_origindex= 1;
 
 	/* check autosmooth and displacement, we then have to skip only-verts optimize
 	 * Note: not sure what we want to give higher priority, currently do_displace
@@ -3201,7 +3197,10 @@ static void init_render_mesh(Render *re, ObjectRen *obr, int timeoffset)
 	do_autosmooth = ((me->flag & ME_AUTOSMOOTH) != 0) && !do_displace;
 	if (do_autosmooth || do_displace)
 		timeoffset = 0;
-	
+
+	/* origindex currently used when using autosmooth, or baking to vertex colors. */
+	need_origindex = (do_autosmooth || ((re->flag & R_BAKING) && (re->r.bake_flag & R_BAKE_VCOL)));
+
 	mask= CD_MASK_BAREMESH|CD_MASK_MTFACE|CD_MASK_MCOL;
 	if (!timeoffset)
 		if (need_orco)