Index: normal.h
===================================================================
--- normal.h	(revision 478)
+++ normal.h	(revision 479)
@@ -15,11 +15,17 @@
 
 __rayapi void raydium_normal_generate_lastest_triangle (int default_visu);
 /**
-Generate normal for the last created triangle (see ##raydium_vertex_index##)
+Generate normals for the last created triangle (see ##raydium_vertex_index##)
 if ##default_visu## is true ( != 0 ), this function will restore "visu" 
 normals too.
 **/
 
+__rayapi void raydium_normal_generate_lastest_tangent(void);
+/**
+Generate tangents for the last created triangle. Internal use.
+**/
+
+
 __rayapi void raydium_normal_restore_all (void);
 /**
 This function restore visu normals with standard ones (##raydium_vertex_normal_*##)