The OpenGL stuff only refers to the live feedback, as you work. When it comes to the rendering of your work, your graphics card has no part in the process - it's all down to memory and CPU performance. As to the actual slowing down of the window with more figures... have you considered hiding all the figures you're not working on at a given moment? If I'm working on one particular area of the scene, especially a crowded one, then I hide away everything but any stuff pertinient to the figure/prop I'm working on at the time, which speeds up the response of the computer some. friendlyrogue