Index: trunk/src/libcschem/cnc_grp.c
===================================================================
--- trunk/src/libcschem/cnc_grp.c	(revision 11151)
+++ trunk/src/libcschem/cnc_grp.c	(revision 11152)
@@ -69,6 +69,7 @@
 	if (strcmp(str, "terminal") == 0)     return CSCH_ROLE_TERMINAL;
 	if (strcmp(str, "wire-net") == 0)     return CSCH_ROLE_WIRE_NET;
 	if (strcmp(str, "junction") == 0)     return CSCH_ROLE_JUNCTION;
+	if (strcmp(str, "extobj-gfx") == 0)   return CSCH_ROLE_EXTOBJ_GFX;
 	return CSCH_ROLE_invalid;
 }
 
Index: trunk/src/libcschem/cnc_obj.c
===================================================================
--- trunk/src/libcschem/cnc_obj.c	(revision 11151)
+++ trunk/src/libcschem/cnc_obj.c	(revision 11152)
@@ -43,6 +43,7 @@
 		case CSCH_ROLE_HUB_POINT:     return CSCH_DSPLY_HUBTERM;
 		case CSCH_ROLE_TERMINAL:      return CSCH_DSPLY_HUBTERM;
 		case CSCH_ROLE_SYMBOL:        return CSCH_DSPLY_SYMBOL;
+		case CSCH_ROLE_EXTOBJ_GFX:    return CSCH_DSPLY_SYMBOL;
 		case CSCH_ROLE_WIRE_NET:      return CSCH_DSPLY_WIRE;
 		case CSCH_ROLE_JUNCTION:      return CSCH_DSPLY_WIRE;
 		case CSCH_ROLE_empty:         return obj->type == CSCH_CTYPE_POLY ? CSCH_DSPLY_BACKGROUND : CSCH_DSPLY_DECORATION; /* top level user grouping */
Index: trunk/src/libcschem/cnc_obj.h
===================================================================
--- trunk/src/libcschem/cnc_obj.h	(revision 11151)
+++ trunk/src/libcschem/cnc_obj.h	(revision 11152)
@@ -262,6 +262,7 @@
 		case CSCH_ROLE_BUS_TERMINAL:
 		case CSCH_ROLE_HUB_POINT:
 		case CSCH_ROLE_TERMINAL:
+		case CSCH_ROLE_EXTOBJ_GFX:
 			return 1;
 		case CSCH_ROLE_SYMBOL:
 			return !sheet->loose_sym;
Index: trunk/src/libcschem/compile.c
===================================================================
--- trunk/src/libcschem/compile.c	(revision 11151)
+++ trunk/src/libcschem/compile.c	(revision 11152)
@@ -761,6 +761,7 @@
 			case CSCH_ROLE_BUS_TERMINAL:
 			case CSCH_ROLE_HUB_POINT:
 			case CSCH_ROLE_JUNCTION:
+			case CSCH_ROLE_EXTOBJ_GFX:
 				break;
 		}
 	}
Index: trunk/src/libcschem/concrete.h
===================================================================
--- trunk/src/libcschem/concrete.h	(revision 11151)
+++ trunk/src/libcschem/concrete.h	(revision 11152)
@@ -110,7 +110,10 @@
 	CSCH_ROLE_SYMBOL,
 	CSCH_ROLE_TERMINAL,
 	CSCH_ROLE_WIRE_NET,
-	CSCH_ROLE_JUNCTION
+	CSCH_ROLE_JUNCTION,
+
+	/* extensions: not in the data model */
+	CSCH_ROLE_EXTOBJ_GFX
 } csch_role_t;
 
 typedef struct csch_comm_str_s {
Index: trunk/src/libcschem/extobj.c
===================================================================
--- trunk/src/libcschem/extobj.c	(revision 11151)
+++ trunk/src/libcschem/extobj.c	(revision 11152)
@@ -31,6 +31,8 @@
 #include <librnd/core/error.h>
 #include <librnd/core/compat_misc.h>
 
+#include "cnc_grp.h"
+
 #include "extobj.h"
 
 /* persistent copy of impl; both key and value are allocated; on unregister
@@ -98,7 +100,37 @@
 	return i;
 }
 
+csch_cgrp_t *csch_extobj_gfx_lookup(csch_cgrp_t *grp)
+{
+	htip_entry_t *e;
 
+	for(e = htip_first(&grp->id2obj); e != NULL; e = htip_next(&grp->id2obj, e)) {
+		csch_cgrp_t *gfx = (csch_cgrp_t *)e->value;
+		if (csch_obj_is_grp(&gfx->hdr) && (gfx->role == CSCH_ROLE_EXTOBJ_GFX))
+			return gfx;
+	}
+
+	return NULL;
+}
+
+csch_cgrp_t *csch_extobj_gfx_clear(csch_sheet_t *sheet, csch_cgrp_t *grp)
+{
+	csch_cgrp_t *gfx = csch_extobj_gfx_lookup(grp);
+
+	if (gfx == NULL) { /* create new empty */
+		csch_source_arg_t *src = csch_attrib_src_c(NULL, 0, 0, NULL);
+		gfx = csch_cgrp_alloc(sheet, grp, csch_oid_new(sheet, &sheet->direct));
+		csch_attrib_set(&gfx->attr, 0, "purpose", "extobj-gfx", src, NULL);
+		gfx->role = CSCH_ROLE_EXTOBJ_GFX;
+		csch_sheet_set_changed(sheet, 1);
+		return gfx;
+	}
+
+	csch_cgrp_clear(gfx);
+	return gfx;
+}
+
+
 void csch_extobj_init(void)
 {
 	htsp_init(&extobjs_impls, strhash, strkeyeq);
Index: trunk/src/libcschem/extobj.h
===================================================================
--- trunk/src/libcschem/extobj.h	(revision 11151)
+++ trunk/src/libcschem/extobj.h	(revision 11152)
@@ -47,8 +47,17 @@
 RND_INLINE void csch_extrobj_attr_edit_pre(csch_cgrp_t *grp, const char *key);
 RND_INLINE void csch_extrobj_attr_edit_post(csch_cgrp_t *grp, const char *key);
 
+/*** for implementing extended objects ***/
 
-/* internal, do not call */
+/* return the extobj-gfx group within grp or NULL if not found */
+csch_cgrp_t *csch_extobj_gfx_lookup(csch_cgrp_t *grp);
+
+/* return the extobj-gfx group within grp after making sure it is empty
+   (creating or clearing it) */
+csch_cgrp_t *csch_extobj_gfx_clear(csch_sheet_t *sheet, csch_cgrp_t *grp);
+
+
+/*** internal, do not call ***/
 void csch_extobj_init(void);
 void csch_extobj_uninit(void);
 const csch_extobj_impl_t *csch_extobj_lookup(const char *name);
Index: trunk/src/libcschem/util_grp.c
===================================================================
--- trunk/src/libcschem/util_grp.c	(revision 11151)
+++ trunk/src/libcschem/util_grp.c	(revision 11152)
@@ -113,6 +113,7 @@
 {
 	switch(grp->role) {
 		case CSCH_ROLE_SYMBOL:
+		case CSCH_ROLE_EXTOBJ_GFX:
 			{
 				static const char *def_pen_sym[] = {"sym-decor", "sheet-decor", NULL};
 				return def_pen_sym;