Soon-Bum Lim

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This paper presents an algorithm to compute an approximation to the general sweep boundary of a 2D curved moving object which changes its shape dynamically while traversing a trajectory. In eeect, we make polygonal approximations to the trajectory and to the object shape at every appropriate instance along the trajectory so that the approximated polygonal(More)
Oriental characters (such as Chinese, Korean, and Japanese characters) are composed of several strokes, and the shape of each stroke is determined by a brush sweep. In the paper, a new representation scheme is proposed for the design of stroke-structured fonts. This approach (called a structured composition of stroke elements) reflects the characteristics(More)
To support collaboration in 3D virtual space, a technology to express the intention directly between collaborators is required. For such method to express the intention the sketch is most effective and this is because the sketch is conventionally able to express the intention quickly, easily and intuitively. Also, the annotation entered through such sketch(More)
The sketch technique, which can quickly and easily make expressions, is very useful in effectively adapting 3D virtual space technology to the collaboration. In order for the sketch technique to apply to the 3D virtual space, we need to solve the problem of inputting 2D sketch to a 3D virtual space and the phase difference that can occur during input. This(More)
We present an algorithm to approximate the variable radius ooset curves by cubic B ezier curves. The ooset curve is approximated by a cubic B ezier curve which interpolates the positions and derivatives of the exact ooset curve at both end points. Thus, it approximates the exact ooset curve very closely near the curve end points, but not necessarily in the(More)
We introduce a multiple-pass sketch-based user interface, designed for novice users, which avoids spatial ambiguities and hence allows considerable freedom in creating 3D animations. The user first draws the path along which a character or object is to move. A vertical motion window is then erected along this path, on which the user specifies the(More)
3D virtual environment provides a limited amount of information, mainly focusing on visual information. This is the main cause of users losing the sense of direction in the environment. Many researches for developing a navigation tools that address this problem have been carried out. In this study, a navigation tool is designed by applying topic map, one of(More)
Navigating in a three dimensional (3D) virtual environment is difficult mainly because of limited navigational information that can only offer a screen-size visualization and low level imitation of other human senses. To address this problem, studies on various methods of navigation aid have been carried out. The navigation aid described in this paper was(More)