--- ray/src/rt/raytrace.c	1993/01/26 09:28:00	2.3
+++ ray/src/rt/raytrace.c	1993/02/23 13:57:11	2.4
@@ -461,6 +461,8 @@ OBJECT  *cxs;
 	checkset(oset, cxs);			/* eliminate double-checking */
 	for (i = oset[0]; i > 0; i--) {
 		o = objptr(oset[i]);
+		if (o->omod == OVOID && issurface(o->otype))
+			continue;		/* ignore void surfaces */
 		(*ofun[o->otype].funp)(o, r);
 	}
 	if (r->ro == NULL)