• Journal of KIISE:Computer Systems and Theory
• /
• v.35 no.1
• /
• pp.44-52
• /
• 2008

In this paper we consider detecting collisions between characters whose motion is specified by motion capture data. Since we are targeting on massive crowd simulation, we only consider rough collisions, modeling the characters as a disk in the floor plane. To provide efficient collision detection, we introduce a hierarchical bounding volume, the Motion Oriented Bounding Box tree (MOBB tree). A MOBBtree stores space-time bounds of a motion clip. In crowd animation tests, MOBB trees performance improvements ranging between two and an order of magnitude.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.1 no.1
• /
• pp.27-35
• /
• 2006

Crowd behaviors on cyber underwater environment are often produced in entertainment contents, such as films and games. It is easy for us to come in contact with the scenes appearing a lot of characters as digital films and animation works are increased gradually, owing to developing of computer graphics. Though the processing a scene of crowd and the behavior system of crowd, related to the processing techniques of crowd behavior in cyber space, have been implemented so far, the research for developing the natural crowd behavior simulator can not be still satisfying. In this paper, we designed a realistic and efficient Fish Schooling Behavior Simulator for the contents production of cyber underwater environment, which showed each type of fish behavior in cyber underwater smartly, and which generated the animating the behavior automatically, reducing the time and cost.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.10
• /
• pp.759-767
• /
• 2006

The level-of-detail (LoD), which is a method of reducing polygons on mesh, is one of the most fundamental techniques in real-time rendering. In this paper, we propose a novel level-of-detail technique applied to the virtual character's motion (Motion LoD). The movement of a virtual character can be defined as the transformation of each joint and it's relation to the mesh. The basic idea of the proposed 'Motion LoD' method is to reduce number of joints in an articulated figure and minimize the error between original and simplified motion. For the motion optimization, we propose an error estimation method and a linear system reconstructed from this error estimation for a fast optimization. The proposed motion simplification method is effectively useful for motion editing and real-time crowd animation.

• Proceedings of the Korea Contents Association Conference
• /
• 2006.05a
• /
• pp.517-520
• /
• 2006

Crowd behavioral scenes in virtual underwater world are presented in many entertainments such as films and games. According to the increase of digital films and animations caused by the development of computer graphics, it is easy for us to meet with the cyber characters in those scenes. Characters which appear in computer animation put life into virtual world. The more characters we have in this virtual space, the deeper we are immersed in the space. There were many researches which processed the crowd scene and implemented the crowd behavior system in Korea. They were related to developing VR contents which were available to feel actually in the construction of the virtual environment. But they are far from reaching the step to put to practical use in developing the crowd behavior modeler. Therefore, we suggestion the fish schooling behavior modeler that provides interaction and action behavior in 3D object to present vividly and effectively in underwater world.

• ETRI Journal
• /
• v.39 no.4
• /
• pp.493-501
• /
• 2017

This paper introduces a new motion-synthesis technique for animating multiple characters. At a high level, we introduce a hub-sub-control-point scheme that automatically generates many different spline curves from a user scribble. Then, each spline curve becomes a trajectory along which a 3D character moves. Based on the given curves, our algorithm synthesizes motions using a cyclic motion. In this process, space-time warp curves, which are time-warp curves, are embedded in the 3D environment to control the speed of the motions. Since the space-time warp curve represents a trajectory over the time domain, it enables us to verify whether the trajectory causes any collisions between characters by simply checking whether two space-time warp curves intersect. In addition, it is possible to edit space-time warp curves at run time to change the speed of the characters. We use several experiments to demonstrate that the proposed algorithm can efficiently synthesize a group of character motions. Our method creates collision-avoiding trajectories ten times faster than those created manually.

• Journal of KIISE:Computing Practices and Letters
• /
• v.15 no.11
• /
• pp.819-830
• /
• 2009

When simulating large crowds, it is inevitable that the models and motions of many characters will be cloned. McDonnell et al. analyzed user's perception to find cloned characters. They established that clones of appearance are far easier to detect than motion clones. In this paper, we expand McDonnell's research[1], with the focus on multiple clones and the appearance variety in real-time game environment. Introducing the perceptual organization, we show the appearance variety of crowd clones by using game items and texture modulation. Other factors that influence the ability to detect clones were examined, such as the moving direction and distance between character clones. Our results provide novel insights and useful thresholds that will assist in creating more realistic crowds of game environments.