is manipulated or animated causing the frame rate to fall below the value specified by the designer the system automatically reduces the scene 39 s rendering quality by selecting the next lower quality rendering subsystem 106a through 106g selected in the option selection boxes 312 and 314 until the frame rate specified by the designer is achieved or the selected object or objects are rendered using the rendering subsystem showing the lowest level of detail when the actions that caused the reduction of the frame rate such as object manipulation or increased computational load due to the activation of background tasks are terminated the rendering quality is returned to the general rendering method at any stage of the process the designer may choose to override the adaptive degradation system and force the system to render the scene using the general rendering technique when the override is in effect the refresh rate may fall below the selected refresh rate when the designer removes the override the adaptive degradation system resumes operation fig4 a through 4d illustrate the user 39 s view of the adaptive degradation system of the present invention in fig4 a the viewport screen 320 is divided into 4 viewports the.