anchor.diff:    (declare (ignore wptr mesh tolerance m4))
     (error "Not implemented"))
   
  -(defun %make-convex-hull-from-points (wptr points tolerance m4)
  +(defn %make-convex-hull-from-points ((wptr foreign-pointer)
  +                                     (points sequence)
  +                                     (tolerance number)
  +                                     (m4 foreign-pointer))
  +    convex-hull-geometry
     (assert (>= (length points) 4))
     (let ((len (length points)))
       (with-foreign-object (p-ptr :float (* 3 len))
  
positive.code:         :ptr (newtoncreatecylinder
                wptr (float radius-0) (float radius-1) (float height) 0 m4))))))
  
  (defun make-chamfer-cylinder-geometry (world &key (radius 1s0) (height 1s0)
                                                 (offset-matrix4 (m4:identity)))
    "Create a ChamferCylinder primitive for collision."
    (let ((wptr (%world-ptr world)))
      (with-foreign-array (m4 offset-matrix4 '(:array :float 16))
        (%init-data
  
negative.code:    zero in tolerance will generate an exact hull and a value langer
     that zero will generate a loosely fitting hull and it willbe faster
     to generate."
    (declare (optimize (speed 3) (safety 1) (debug 1)))
    (let ((wptr (%world-ptr world)))
      (with-foreign-array (m4 offset-matrix4 '(:array :float 16))
        (%init-data
  