+redef class OffsetPoint3d
+ redef fun x=(v)
+ do
+ if isset _x and v != x then needs_update
+ super
+ end
+
+ redef fun y=(v)
+ do
+ if isset _y and v != y then needs_update
+ super
+ end
+
+ redef fun z=(v)
+ do
+ if isset _z and v != z then needs_update
+ super
+ end
+end
+