Visualization of regular maps : the chase continues

A regular map is a symmetric tiling of a closed surface, in the sense that all faces, vertices, and edges are topologically indistinguishable. Platonic solids are prime examples, but also for surfaces with higher genus such regular maps exist. We present a new method to visualize regular maps. Space models are produced by matching regular maps with target shapes in the hyperbolic plane. The approach is an extension of our earlier work. Here a wider variety of target shapes is considered, obtained by duplicating spherical and toroidal regular maps, merging triangles, punching holes, and gluing the edges. The method produces about 45 new examples, including the genus 7 Hurwitz surface

A model for strategy in constraint solving

The use of constraints for the definition of graphical user interfaces has been recognized as a great concept. However, often many valuations of the variables will satisfy the constraints, and which particular valuation matches best with the expectation of the user cannot be decided without further information. Three typical examples of user interfaces are presented where this occurs, and from these, requirements on a more cooperative constraint solver are derived. A new method for the definition and implementation of the strategy to decide which variables to adapt is presented. The model is based on two notions: hierarchy and grouping. Variables are divided into groups, and for each group three parameters are set. These are used to determine the level of variables, dependent on which group they belong, and which variables are modified. These levels are used in turn to select the variables to be adapted. An implementation of this method is described, as part of the Computational Steering Environment (CSE) developed at CWI. The resulting constraint solver can handle simultaneous sets of non-linear, multi-way constraints; and can handle a high-level definition of the strategy to be followed. Finally, the results are discussed, and suggestions for further work are done

Steering smog prediction

The use of computational steering for smog prediction is described. This application is representative for many underlying issues found in steering high performance applications: high computing times, large data sets, and many different input parameters. After a short description of the smog prediction model, its visualization and steering are described. The amount of computation needed to solve the governing transport equations is alarmingly high. The user has a large number of options for the display of various aspects of the simulation, and also for the interactive control of its input data. Smooth animation is very important to monitor the evolution of pollutants and for a responsive feedback to parameter changes. Here a performance of least 15 frames per second is required. We discuss techniques that allow the user to steer the numerical solver, such that an optimal tradeoff between computation speed and accuracy can be made

CSE: a modular architecture for computational steering

Computational steering is the ultimate goal of interactive simulation. Steering enables users to supervise and dynamically control the computation of an ongoing simulation. We describe CSE: a modular architecture for a computational steering environment. The kernel of the architecture is designed to be very simple, flexible and minimalistic. All higher level system functionality is pushed into modular components outside of the kernel, resulting in a rich and powerful environment. For these modular components (called satellites) a uniform user interface metaphor for users, based on a tray of cards, has been used. The card tray metaphor is very simple to understand and provides users with a simple mechanism to organize and retrieve the tools. Several applications of the environment are shown

Myriahedrale projecties : de wereld uitgevouwen

Myriahedrale projecties zijn een nieuwe klasse van methodes om wereldkaarten te maken. Het principe is eenvoudig: de globe wordt opgedeeld in een zeer groot aantal facetten en vervolgens wordt deze in facetten ingedeelde bol uitgevouwen. Dit leidt tot projecties vrijwel zonder vervorming, maar natuurlijk wel met veel onderbrekingen. Door te variëren met de opdeling en de wijze van uitvouwen kunnen allerlei onverwachte afbeeldingen van de wereld worden verkregen

Parametrizable cameras for 3D computational steering

We present a method for the definition of multiple views in 3D interfaces for computational steering. The method uses the concept of a point-based parametrizable camera object. This concept enables a user to create and configure multiple views on his custom 3D interface in an intuitive graphical manner. Each view can be coupled to objects present in the interface, parametrized to (simulation) data, or adjusted through direct manipulation or user defined camera controls. Although our focus is on 3D interfaces for computational steering, we think that the concept is valuable for many other 3D graphics applications as well