anchor.diff:      (setf (world-solver-model world) solve-model)
       (setf (world-friction-model world) friction-model)
       world))
  +
  +;; {todo} turn into doc
  +;; Create an instance of the Newton world. This function does the same
  +;; as NewtonCreate, except that it accepts an extra argument to
  +;; specify the stack size for each thread. This is only useful for
  +;; simulation with very many (ie thousands or more objects). If in
  +;; doubt, use NewtonCreate as it uses reasonable defaults.
  +
  +;;------------------------------------------------------------
  +
  +(defun %world-from-world-ptr (world-ptr)
  +  (let ((id (pointer-address (newtonworldgetuserdata world-ptr))))
  +    (%world-by-id id)))
   
   ;;------------------------------------------------------------
   
  
positive.code:                              :solve-model solve-model
                               :friction-model friction-model
                               :min-frame-rate minimum-frame-rate))))
      (unless (eq broadphase-algorithm :default)
        (setf (world-broadphase-algorithm world) broadphase-algorithm))
      (unless (eq max-thread-count :default)
  
negative.code: ;; newtonworldconvexcast
  ;; newtonworldconvexcastreturninfo
  ;;
  
  
  ;; newtonworldgetbodycount
  ;; newtonworldgetconstraintcount
  ;; newtonworldgetfirstmaterial
  