Index: export_stl.c
===================================================================
--- export_stl.c	(revision 31019)
+++ export_stl.c	(revision 31020)
@@ -213,7 +213,7 @@
 	else thick = pcb_board_thickness(PCB, "stl", PCB_BRDTHICK_PRINT_ERROR);
 	if (thick <= 0) {
 		rnd_message(RND_MSG_WARNING, "STL: can not determine board thickness - falling back to hardwired 1.6mm\n");
-		thick = PCB_MM_TO_COORD(1.6);
+		thick = RND_MM_TO_COORD(1.6);
 	}
 
 	if (options[HA_zcent].lng)