Friends, I am not sure that my problem/question will be interesting for everyone, but the beginners. Imagine you are making some modeling, some physical visualisation, like an object on the incline where you are interested in the time of the body going down when friction is the function of time [ T(t) ] and velocity [ V(v) ]. This task assumes the program recieving messages (wm_message): WM_MOUSEMOVE or smth.. -> 1. What class should catch the message?! Where do I have to place it? (meaning MFC usage) 2. How do I have to manage the drawing function? CALLBACK drawscene(void){ switch (scene_flag){ case 1: scene1(); break; case 2: scene2(); break; ... ... case N: sceneN(); break; default: DEFAULTCODE(); } } And manage the play by changing the scene_flag by messages... Does it make sense? Or there is smth much more simple and tuned method of this. Thanx a lot for any comments and your time. If there is any idea about this kalenkov@dkhome.ru