Index: trunk/src/libcschem/intersect.c
===================================================================
--- trunk/src/libcschem/intersect.c	(revision 2240)
+++ trunk/src/libcschem/intersect.c	(revision 2241)
@@ -41,6 +41,7 @@
 csch_inline void isc_append(g2d_vect_t **dst, long *dst_len, g2d_vect_t *src, long src_len)
 {
 	long n;
+
 	for(n = 0; n < src_len; n++) {
 		if (*dst_len == 0)
 			return;
@@ -53,18 +54,26 @@
 
 csch_inline long isc_ll(csch_line_t *l1, csch_line_t *l2, g2d_vect_t *iscp, long iscp_len)
 {
-	g2d_vect_t ip[2];
-	int res = g2d_iscp_cline_cline(&l1->inst.c, &l2->inst.c, ip, NULL);
-	isc_append(&iscp, &iscp_len, ip, res);
-	return res;
+	if (iscp != NULL) {
+		g2d_vect_t ip[2];
+		int res = g2d_iscp_cline_cline(&l1->inst.c, &l2->inst.c, ip, NULL);
+		isc_append(&iscp, &iscp_len, ip, res);
+		return res;
+	}
+	else
+		return g2d_isc_sline_sline(&l1->inst, &l2->inst);
 }
 
 csch_inline long isc_la(csch_line_t *l, csch_arc_t *a, g2d_vect_t *iscp, long iscp_len)
 {
-	g2d_vect_t ip[2];
-	int res = g2d_iscp_cline_carc(&l->inst.c, &a->inst.c, ip, NULL, 0);
-	isc_append(&iscp, &iscp_len, ip, res);
-	return 0;
+	if (iscp != NULL) {
+		g2d_vect_t ip[2];
+		int res = g2d_iscp_cline_carc(&l->inst.c, &a->inst.c, ip, NULL, 0);
+		isc_append(&iscp, &iscp_len, ip, res);
+		return 0;
+	}
+	else
+		return g2d_isc_sline_sarc(&l->inst, &a->inst);
 }
 
 csch_inline long isc_aa(csch_arc_t *a1, csch_arc_t *a2, g2d_vect_t *iscp, long iscp_len)
@@ -79,6 +88,7 @@
 
 csch_inline long isc_pp(csch_cpoly_t *p1, csch_cpoly_t *p2, g2d_vect_t *iscp, long iscp_len)
 {
+
 	return 0;
 }
 
Index: trunk/src/libcschem/intersect.h
===================================================================
--- trunk/src/libcschem/intersect.h	(revision 2240)
+++ trunk/src/libcschem/intersect.h	(revision 2241)
@@ -27,5 +27,10 @@
 #include <libcschem/concrete.h>
 
 /* Return number of intersections between o1 and o2; optionally loads iscp
-   with intersection points, up to iscp_len */
+   with intersection points, up to iscp_len. If iscp is NULL, precise
+   intersection caclulation is done usign thickness of objects and the number
+   of different object-object intersections is returned. If iscp is not NULL,
+   only centerline-intersections are considered and iscp coords are all on
+   object centerlines (number of total centerline iscs returned, may be
+   larger than iscp_len) */
 long csch_obj_intersect_obj(csch_sheet_t *sheet, csch_chdr_t *o1, csch_chdr_t *o2, g2d_vect_t *iscp, long iscp_len);