diff --git a/source/blender/render/intern/source/convertblender.c b/source/blender/render/intern/source/convertblender.c
index a9e2e1c..0799abd 100644
--- a/source/blender/render/intern/source/convertblender.c
+++ b/source/blender/render/intern/source/convertblender.c
@@ -548,10 +548,11 @@ static VertRen *as_findvertex_lnor(VlakRen *vlr, VertRen *ver, ASvert *asv, cons
 		for (a = 0; a < 4; a++) {
 			if (asf->vlr[a] && asf->vlr[a] != vlr) {
 				/* this face already made a copy for this vertex! */
-				if (asf->nver[a]) {
-					if (equals_v3v3(lnor, asf->nver[a]->n)) {
-						return asf->nver[a];
-					}
+				VertRen *nver = asf->nver[a];
+
+				/* this face already made a copy for this vertex! */
+				if (!ELEM(nver, NULL, ver) && equals_v3v3(lnor, nver->n)) {
+					return nver;
 				}
 			}
 		}
@@ -583,8 +584,8 @@ static void as_addvert_lnor(ObjectRen *obr, ASvert *asv, VertRen *ver, VlakRen *
 		v1 = RE_vertren_copy(obr, ver);
 		copy_v3_v3(v1->n, lnor);
 	}
+	asf->nver[asf_idx] = v1;
 	if (v1 != ver) {
-		asf->nver[asf_idx] = v1;
 		if (vlr->v1 == ver) vlr->v1 = v1;
 		if (vlr->v2 == ver) vlr->v2 = v1;
 		if (vlr->v3 == ver) vlr->v3 = v1;
@@ -592,6 +593,110 @@ static void as_addvert_lnor(ObjectRen *obr, ASvert *asv, VertRen *ver, VlakRen *
 	}
 }
 
+static bool as_ver_in_array(VertRen *ver, VertRen **arr, int size)
+{
+	VertRen **ver_it = arr;
+	int a;
+
+	for (a = 0; a < size && *ver_it != ver; ++a, ++ver_it) {}
+
+	return (a != size);
+}
+
+static void as_tweak_vcos(ASvert *asv)
+{
+	ASface *asf;
+	const float fac = 1e-4f;
+	const int tot_asf = asv->totface;
+	int a, tot_done_verts = 0;
+
+	VertRen *done_verts_buff[16] = {
+	    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+	};
+	VertRen **done_verts = (tot_asf < 17) ? done_verts_buff : MEM_callocN(sizeof(VertRen *) * tot_asf, __func__);
+
+	VertRen *work_verts_buff[32] = {
+	    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+	    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+	};
+	VertRen **work_verts = (tot_asf < 17) ? work_verts_buff : MEM_callocN(sizeof(VertRen *) * tot_asf * 2, __func__);
+
+	asf = asv->faces.first;
+	while (asf) {
+		for (a = 0; a < 4; ++a) {
+			VertRen *ver = asf->nver[a];
+			float n[3], d[3] = {0.0f, 0.0f, 0.0f};
+			ASface *asf_it = asf;
+			int b = a, tot_work_verts = 0;
+
+			if (!ver || as_ver_in_array(ver, done_verts, tot_asf)) {
+				continue;
+			}
+
+			/* this ver has not yet been handled. */
+			while (asf_it) {
+				for (; b < 4; ++b) {
+					if (asf_it->nver[b] == ver) {
+						VlakRen *vlr = asf_it->vlr[b];
+						VertRen *v1, *v2;
+
+						BLI_assert(vlr != NULL);
+
+						if (ver == vlr->v1) {
+							v1 = vlr->v2;
+							v2 = vlr->v4 ? vlr->v4 : vlr->v3;
+						}
+						else if (ver == vlr->v2) {
+							v1 = vlr->v3;
+							v2 = vlr->v1;
+						}
+						else if (ver == vlr->v3) {
+							v1 = vlr->v4 ? vlr->v4 : vlr->v1;
+							v2 = vlr->v2;
+						}
+						else if (ver == vlr->v4) {
+							v1 = vlr->v1;
+							v2 = vlr->v3;
+						}
+
+						if (!as_ver_in_array(v1, work_verts, tot_work_verts)) {
+							sub_v3_v3v3(n, ver->co, v1->co);
+							madd_v3_v3fl(d, n, fac);
+							work_verts[tot_work_verts++] = v1;
+						}
+						if (!as_ver_in_array(v2, work_verts, tot_work_verts)) {
+							sub_v3_v3v3(n, ver->co, v2->co);
+							madd_v3_v3fl(d, n, fac);
+							work_verts[tot_work_verts++] = v2;
+						}
+
+						BLI_assert(tot_work_verts <= tot_asf * 2);
+					}
+				}
+
+				b = 0;
+				asf_it = asf_it->next;
+			}
+
+			if (!is_zero_v3(d)) {
+				add_v3_v3(ver->co, d);
+			}
+
+			done_verts[tot_done_verts++] = ver;
+
+			BLI_assert(tot_done_verts <= tot_asf);
+		}
+		asf = asf->next;
+	}
+
+	if (done_verts != done_verts_buff) {
+		MEM_freeN(done_verts);
+	}
+	if (work_verts != work_verts_buff) {
+		MEM_freeN(work_verts);
+	}
+}
+
 /* note; autosmooth happens in object space still, after applying autosmooth we rotate */
 /* note2; actually, when original mesh and displist are equal sized, face normals are from original mesh */
 static void autosmooth(Render *UNUSED(re), ObjectRen *obr, float mat[4][4], short (*lnors)[4][3])
@@ -624,13 +729,14 @@ static void autosmooth(Render *UNUSED(re), ObjectRen *obr, float mat[4][4], shor
 		}
 	}
 
-	/* free */
+	/* tweak slightly coordinates of 'split' vertices, to avoids blackdots artifacts (see T39735), and free.*/
 	for (a = 0; a < totvert; a++) {
+		as_tweak_vcos(&asverts[a]);
 		BLI_freelistN(&asverts[a].faces);
 	}
 	MEM_freeN(asverts);
 
-	/* rotate vertices and calculate normal of faces */
+	/* rotate vertices */
 	for (a = 0; a < obr->totvert; a++) {
 		ver = RE_findOrAddVert(obr, a);
 		mul_m4_v3(mat, ver->co);
@@ -640,6 +746,7 @@ static void autosmooth(Render *UNUSED(re), ObjectRen *obr, float mat[4][4], shor
 			normalize_v3(ver->n);
 		}
 	}
+	/* calculate normal of faces */
 	for (a = 0; a < obr->totvlak; a++) {
 		vlr = RE_findOrAddVlak(obr, a);