High performance virtual clothing dynamics

There are three major problems in modeling the natural motion of virtual clothing in a 3D environment: (1) a large number of contact points, (2) the computations of collision information in the presence of numerical errors, and (3) interactions with objects having sharp features. This thesis proposes new techniques that successfully address these three problems. The results show that these new techniques can be applied on virtual garments with complex geometry and on unique interactions between continuous and non-smooth surfaces. Our techniques are classified into four categories: (1) culling non-colliding subsurfaces in collision detection, (2) intrinsic collision detection, (3) collision response, and (4) the editing and simulation of special virtual garments. For culling non-colliding subsurfaces in collision detection, we propose an imagebased method for interference test, a method of decomposition of a surface into a new type of (π ,β ,I)-surfaces for exact collision detection in the time domain and an adaptive backward voxel-based hierarchical structure for dealing with highly compressed deformable surfaces. For intrinsic collision detection, we propose a new system architecture. Robust treatments of numerical errors are devised. For collision response, a penetration-free motion space is proposed for handling features involved in multiple collision events, and a static analysis method is suggested for handling friction and stiction. Thus, interactions with objects having sharp features are handled efficiently. For the editing and simulation of special virtual garments, we propose techniques to handle multi-layered surfaces, surfaces with sharp features and sewn surfaces. A multilayered surface is constructed by gluing several surfaces together either along lines or over regions. A surface with sharp features is represented by two meshes. A sewn surface is obtained by systematically performing a stable sewing process. These techniques have been integrated into a high performance system for virtual clothing dynamics

Training in corruption prevention

published_or_final_versionPublic AdministrationMasterMaster of Social Science

Hardware-assisted virtual collisions

Abstract not available

Optimized evacuation route based on crowd simulation

Abstract An evacuation plan helps people move away from an area or a building. To assist rapid evacuation, we present an algorithm to compute the optimal route for each local region. The idea is to reduce congestion and maximize the number of evacuees arriving at exits in each time span. Our system considers crowd distribution, exit locations, and corridor widths when determining optimal routes. It also simulates crowd movements during route optimization. As a basis, we expect that neighboring crowds who take different evacuation routes should arrive at respective exits at nearly the same time. If this is not the case, our system updates the routes of the slower crowds. As crowd simulation is non-linear, the optimal route is computed in an iterative manner. The system repeats until an optimal state is achieved. In addition to directly computing optimal routes for a situation, our system allows the structure of the situation to be decomposed, and determines the routes in a hierarchical manner. This strategy not only reduces the computational cost but also enables crowds in different regions to evacuate with different priorities. Experimental results, with visualizations, demonstrate the feasibility of our evacuation route optimization method