[CCRG researchers use a variety of visualization software to produce 1-D, 2-D, and 3-D visualizations of numerical relativity and astrophysics simulations.
The group also collaborate with the Einstein Toolkit (ET) consortium (einsteintoolkit.org), an open software community for numerical relativity and relativistic astrophysics to take advantage of petascale computers and advanced cyber infrastructure. The ET consortium includes over 200 researchers across the world. We also works together with computer scientists at the National Center for Supercomputing Applications (NCSA) to run and visualize our simulations on the Blue Waters supercomputer, one of the most powerful supercomputers in the world.
For our studies of black hole mergers, we have used Spiegel, an in-house framework developed by Bischof, which focuses on the data flow model to implement visualization systems. Most of these visualizations are used to promote research at RIT and to the wider community, and for education and outreach purposes. One example is the AstoDance project which uses 3D visualizations to connect hard of hearing students with astrophysical phenomena and dance performances. Visualizations are also produced for the annual Imagine RIT exhibit, presentations to K-12 students, research seminars and colloquia given at RIT and at other institutions. A small selection of movies generated with this framework can be found here here. For more information see here.
We use software such as IDL as well as publicly available tools such as Python, SciPy, and VisIt to visualize our simulations of hydrodynamics simulations, e.g. magnetized gas around supermassive black hole systems. Because most of these simulations typically produce 1-10TB, with each 3D data set taking up ~10GB of space, we use HDF5 data format to store the data on our local CCRG cluster facilities, or on the Blue Waters system at NCSA.
THE SPIEGEL PROJECT
Faculty at the CCRG designed and implemented a extensible and powerful, visualization system named `Spiegel', which uses the data flow model to implement visualization systems. Spiegel is extremely flexible and allows one to visualize data in 3-D space, which allows the exploration of the data in time and space. Many visualizations have been created and used to interpret the science behind the data.
Visualization describes the process of converting numbers into a form we can see visually In order to make the images more comprehensible, it is important to be able to change the visible aspects of an image dynamically For example, the position of the camera can be moved to focus the attention of the viewer, or the transparency of objects can be changed to expose otherwise hidden features Visualizations are typically not composed of a single image because they usually contain a time element â€“ that is, the image varies from one time to the next Movies are the typical result of visualization attempt We developed a language and visualization environment which allows modifications to the visualization parameters â€“ i.e transparency and color of the object, camera position, camera focus point, camera up-vector, and surface luminance; in other words every visual attribute is controlled by a program This language, although it has the ability to control all of these variables, is also extremely simple and can be learned in less than ten minutes.
The qwerty keyboard and a mouse are still the main input devices used today. The last upgraded mouse was introduced by Apple in 2009; the Magic Mouse. The Magic Mouse is a multi touch mouse and can be used to recognize simple gestures. Computer games and visualization environments are typically played out in a 3D world projected on a 2D screen, or a 3D environment. A 2D mouse is not very useful in a 3D environment. On July 2013 Leap Motion released a device which can be used as a 3 dimensional mouse. ` The question is how can gesture recognition be used to control a visualzation environment. What kind of gestures are natural in order to control a viewpoint position keeping in mind that the viewpoint may have to move very large distance or very small distances.
Visualization of data has a long history. The process converts data into a form which is easier to comprehend: something our eyes can see. Sight is one of our best-developed senses, therefore this process can provide a result which gives us faster and easier insight in a complex world. Visualization is, in mathematical terms, a conversion of n-dimensional data to k dimension(s); and k is significantly less than n. Precedented only by sight, hearing can be considered the second most developed sense. Therefore it makes sense to use audio as one additional dimension for the understanding of data. The sense of sight differs significantly from the sense of hearing in resolution and meaning. A visual can be have many details while a sound describing data can only have broad strokes. A visual can be printed and can be used to publish visualization results. Sound describing a data set can be created, but it certainly is not easy to publish. The question is what kind of audio represents scientific data well for a human.
A visualization framework can be seen as a solution to a specialized data flow problem. $Spiegel (Spiegel is the German word for mirror. Like the mirror in a telescope helps to observe the universe, Spiegel helps to observer the simulation of objects in space.) is a visualization framework which uses the Unix pipeline model to execute programs to visualize scientific data. A visualization program in Spiegel is constructed out of small, simple components which communications endpoints are connected together. We are interested in undererstanding how to construct a dataflow allowing to distribte the componets in an eficient and easy-to-use way.
Contact: Hans-Peter Bischof. Working in this area are several graduate and undergraduate students.
Projects and Collaborations: