Please tell me, what is the main idea of such kind of dynamic creation? I recommend you to create an Active Object and set its replication to zero. So you will be able to add the instance of this Active Object and define its parameters in runtime by using the following method: add_activeObjectName(parameter1, parameter2, ...);

I have solved the problem by referring to your suggestion. thank you very much. my intent is to create some instances with different shapes. these instances are from the same active object class. I first create some instances with add_activeObject(...). Then set shape-relevant properties of every instance (setX, setY, setDX, setDY,...). Thus, though these instances are from the same active object class, they prossess different shapes.