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Now showing 1 - 5 of 5
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    Guided Exploration with Dynamic Potential Fields: the Cubical Path System
    (Blackwell Publishers Ltd and the Eurographics Association, 2001) Beckhaus, Steffi; Ritter, Felix; Strothotte, Thomas
    Exploring unknown models or scenes is a highly interactive and dynamic process. Systems for automatic presentation of models or scenes either require cinematographic rules, direct human interaction, framesets, or pre-calculation of paths to a known goal. In this paper we present a system which can deal with rapidly changing user interest in objects of a scene or model as well as with dynamic models and changes of the camera position introduced interactively by the user or through cuts. We describe CubicalPath, a new potential field-based camera control system that helps with the exploration of virtual environments.
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    How to Render Frames and Influence People
    (Blackwell Science Ltd and the Eurographics Association, 1994) Strothotte, Thomas; Preim, Bernhard; Raab, Andreas; Schumann, Jutta; Forsey, David R.
    Rendering systems generally treat the production of images as an objective process governed by the laws of physics. However, perception and understanding on the part of viewers are subjective processes influenced by a variety offactors. For example, in the presentation of architectural drawings, the apparent precision with which the drawings are made will affect whether the viewer considers the design as part of a preliminary design or as part of a final polished project, and to some extent the level of confidence the viewer has in the encoded information.In this paper we develop techniques for rendering images in a way that differs from the usual photorealistic or wire-frame output of renderers. In particular, our techniques allow a user to adjust the rendering of a scene to produce images using primitives with variable degrees of precision, from approximations that resemble vague"five-minute-sketches" to more mature but still hand-drawn images. We provide a theoretical framework for analysing the information flow from the computer to the user via such images. Finally, we describe the design and implementation of a prototypical renderer and show examples of its output.
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    Floating Points: A Method for Computing Stipple Drawings
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Deussen, Oliver; Hiller, Stefan; Van Overveld, Cornelius; Strothotte, Thomas
    We present a method for computer generated pen-and-ink illustrations by the simulation of stippling. In a stipple drawing, dots are used to represent tone and also material of surfaces. We create such drawings by generating an initial dot set which is then processed by a relaxation method based on Voronoi diagrams. The point patterns generated are approximations of Poisson disc distributions and can also be used for integrating functions or the positioning of objects. We provide an editor similar to paint systems for interactively creating stipple drawings. This makes it possible to create such drawings within a matter of hours, instead of days or even weeks when the drawing is done manually.
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    A Camera Engine for Computer Games: Managing the Trade-Off Between Constraint Satisfaction and Frame Coherence
    (Blackwell Publishers Ltd and the Eurographics Association, 2001) Halper, Nicolas; Helbing, Ralf; Strothotte, Thomas
    Many computer games treat the user in the "1st person" and bind the camera to his or her view. More sophistication in a game can be achieved by enabling the camera to leave the users' viewpoint. This, however, requires new methods for automatic, dynamic camera control. In this paper we present methods and tools for such camera control. We emphasize guiding camera control by constraints; however, optimal constraint satisfaction tends to lead to the camera jumping around too much. Thus, we pay particular attention to a trade-off between constraint satisfaction and frame coherence. We present a new algorithm for dynamic consideration of the visibility of objects which are deemed to be important in a given game context.
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    Walk-Through Illustrations: Frame-Coherent Pen-and-Ink Style in a Game Engine
    (Blackwell Publishers Ltd and the Eurographics Association, 2001) Freudenberg, Bert; Masuch, Maic; Strothotte, Thomas
    In this paper we show how a game engine designed to generate photorealistic images can be extended to produce non-photorealistic and hybrid renditions. We introduce new hardware-based methods to accomplish pen-and-ink illustrations. The combination of the highly optimized processing of a game engine and the use of hardware for NPR algorithms yields real-time animation of pen-and-ink illustrations.The particular advance of this method is that it yields the first real-time, frame-coherent pen-and-ink animations which maintain both tone and texture.