Abstract
We present non-photorealistic rendering techniques that depict the motion of 3D rigid objects in a still image extracted from a 3D animation sequence. In order to represent fast moving 3D objects in a still image, the motion blur technique has been employed. However, it is too expensive to render various kinds of motions in real time. Several non-photorealistic rendering approaches have been proposed to represent motions of 3D objects using “speed lines”. To draw speed lines, vertices of 3D object contours on a projected screen plane are detected from several frames. They are connected and drawn along motion tracks of 3D objects. However, users are required to select “speed line” types suited to motion speed of the objects manually and repeatedly. We propose non-photorealistic rendering techniques that depict various kinds of motion of 3D objects automatically and in real time. To realize these techniques, first, a combined motion is decomposed into a translation motion of the center of gravity of the object and its rotational motion, and then each motion is depicted. Experimental results verify our technique is effective enough to depict automatically various motions of 3D objects in real time.
