In this paper, we present a simple and practical method for determining the front-facing polygons for static, dynamic, and deformable objects. The object space is considered a set of open-frustum regions. A bit string associated with each region records polygons for their extended positive half space intersecting the corresponding region. For a given viewpoint, the bit string of the set of the front facing polygons can be determined in a constant time. While objects continuously keep deforming and/or remain in motion in each frame, we update set of bit strings, determined as minimal as possible by the spatial coherence, making our method still perform efficiently.