Index: trunk/src/plugins/rt_topo/crbs_cdt.c
===================================================================
--- trunk/src/plugins/rt_topo/crbs_cdt.c	(revision 1370)
+++ trunk/src/plugins/rt_topo/crbs_cdt.c	(revision 1371)
@@ -117,6 +117,7 @@
 			case RTRND_LINE:
 				cop = obj->line.thickness/2;
 				clr = obj->line.clearance;
+				if (clr < 0) clr = 0;
 				p1 = crbs_make_point(crbs, obj->line.cline.p1.x, obj->line.cline.p1.y, cop, clr, NULL);
 				if ((obj->line.cline.p1.x != obj->line.cline.p2.x) || (obj->line.cline.p1.y != obj->line.cline.p2.y)) {
 					p2 = crbs_make_point(crbs, obj->line.cline.p2.x, obj->line.cline.p2.y, cop, clr, NULL);