From 3ff0943806a39ef5c0624a624aa82230c29d93e1 Mon Sep 17 00:00:00 2001
From: Kaveh Kardan <103860793+kaveh808@users.noreply.github.com>
Date: Tue, 18 Jul 2023 13:53:06 -1000
Subject: [PATCH] Update ray.lisp

No error if shape intersect method not defined.
---
 src/kernel/ray.lisp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/kernel/ray.lisp b/src/kernel/ray.lisp
index 7537e66..7cbd4a5 100644
--- a/src/kernel/ray.lisp
+++ b/src/kernel/ray.lisp
@@ -31,8 +31,10 @@
             (setf min-distance distance)))))
     min-distance))
 
+;;; ignore shapes for which the method is not defined; do not throw error
 (defmethod intersect ((self ray) (shape shape))
-  (error "INTERSECT not implemented"))
+  nil)
+;;  (error "INTERSECT not implemented"))
 
 (defmethod intersect ((self ray) (polyh polyhedron))
   (multiple-value-bind (lo hi) (get-bounds-world polyh)