Index: source/blender/collada/GeometryExporter.cpp
===================================================================
--- source/blender/collada/GeometryExporter.cpp	(revision 46347)
+++ source/blender/collada/GeometryExporter.cpp	(working copy)
@@ -177,7 +177,7 @@
 	// sets material name
 	if (ma) {
 		std::ostringstream ostr;
-		ostr << translate_id(id_name(ma)) << material_index+1;
+		ostr << translate_id(id_name(ma));
 		polylist.setMaterial(ostr.str());
 	}
 			
Index: source/blender/collada/InstanceWriter.cpp
===================================================================
--- source/blender/collada/InstanceWriter.cpp	(revision 46347)
+++ source/blender/collada/InstanceWriter.cpp	(working copy)
@@ -52,7 +52,7 @@
 			std::string matid(get_material_id(ma));
 			matid = translate_id(matid);
 			std::ostringstream ostr;
-			ostr << translate_id(id_name(ma)) << a+1;
+			ostr << translate_id(id_name(ma));
 			COLLADASW::InstanceMaterial im(ostr.str(), COLLADASW::URI(COLLADABU::Utils::EMPTY_STRING, matid));
 			
 			// create <bind_vertex_input> for each uv map