Index: concrete_arc.h
===================================================================
--- concrete_arc.h	(revision 528)
+++ concrete_arc.h	(revision 529)
@@ -28,13 +28,15 @@
 #ifndef CSCH_CONCRETE_ARC_H
 #define CSCH_CONCRETE_ARC_H
 #include "libcschem/concrete.h"
+#include GENGEO2D_TYPECFG
+#include "gengeo2d/sarc.h"
 
 /* type=CSCH_CTYPE_ARC */
 
 typedef struct csch_arc_s {
 	csch_chdr_t hdr;
-	double sang, dang;
-	csch_coord_t cx, cy, rx, ry, sx, sy, ex, ey;
+	g2d_sarc_t prim;
+	csch_coord_t sx, sy, ex, ey; /* cached start/end coords */
 	unsigned svalid:1;
 	unsigned evalid:1;
 } csch_carc_t;