Browsing by Subject "Visibility culling"

Now showing 1 - 3 of 3

Open Access
Increasing the sense of presence in a simulation environment using image generators based on visual attention
(M I T Press, 2010-12) Ciflikli, B.; İşler, V.; Güdükbay, Uğur
Flight simulator systems generally use a separate image-generator component. The host is responsible for the positional data updates of the entities and the image generator is responsible for the rendering process. In such systems, the sense of presence is decreased by model flickering. This study presents a method by which the host can minimize model flickering in the image-generator output. The method is based on preexisting algorithms, such as visibility culling and level of detail management of 3D models. The flickering is minimized for the visually important entities at the expense of increasing the flickering of the entities that are out of the user's focus using a new perception-based approach. It is shown through user studies that the new proposed approach increases the participants' sense of presence. © 2011 by the Massachusetts Institute of Technology.
Open Access
Real-time walkthrough of complex environments
(1997-09) Selçuk, Alper
One of the biggest problems in computer graphics is displaying huge geometric models in interactive frame-rates. Such models exceed limits of best graphics workstations. A lot of work has been done for achieving the required frame-rates in architecture, simulation, computer-aided design and entertainment applications. In this thesis, a survey of methods that enable walkthrough of huge geometric models is done and a system for walkthrough is developed. The system uses hierarchical triangulated geometric models as input. In preprocessing phase, multiresolution models of objects in the scene are created using polygonal simplification techniques. During walkthrough, fast frustum culling based on bounding boxes is performed which eliminates branches of hierarchy that are not visible to camera efficiently. Appropriate level of detail of objects are selected and displayed depending on the distance of the objects to the camera. For far nodes of hierarchy, geometric data in lower levels is ignored and textured bounding box is displayed. The system achieves interactive frame rates for moderate level models, however it is far from being interactive with huge models.
Open Access
Walkthrough in complex environments at interactive rates using level-of-detail
(TÜBİTAK, 2002) Selçuk, Alper; Güdükbay, Uğur; Özgüç, Bülent
One of the biggest problems in computer graphics is displaying huge geometric models at interactive rates. A lot of work has been done to achieve the required frame-rates in architecture, simulation, computer-aided design and entertainment applications. In this paper, a system that enables walkthrough in complex environments using level-of-detail approximations is explained. The system uses hierarchical triangulated models as input. In the preprocessing phase, multiresolution models of objects are created using polygonal simplification techniques. During walkthrough, fast frustum culling based on bounding boxes is performed to eliminate branches of hierarchy that are not visible. An appropriate level for detail of objects is selected and displayed depending on the distance of the objects to the camera. For far nodes in the hierarchy, geometric data in lower levels is ignored and textured bounding boxes are displayed. The system achieves interactive frame rates for moderately complex models containing up to a million polygons.