Participants: Jon Marbach, Jing Fang Progress: The above image is a screen shot taken from an application running on a pc. The app was built with vrJuggler - an open source, platform independent, device independent, virtual reality environment manager. The concept behind vrJuggler is "Code Once, Experience Everywhere", and the advantage to us is that some development can go on outside of the bp Visualization Center. In theory then code can be brought over and compiled with only minor modifications; later I will discuss the realities of the situation. The model you are seeing is based on a piece of an architecture firm's model for a light-rail stop in Houston. (A rendering of this scene is at the top of the Project Description page.) Using a modeling tool, the pieces of the waiting area were extracted. At that point, the model was only shaded in solid colors: grey and orange. Drawing from a large library of digital photographs of SUNY Fredonia (Jon's previous school), images were selected and manipulated to be used as textures for the various parts of the model. Missing File (/dlc-2002/uploads/textures.jpg) A "texture" is somewhat of a misnomer - a texture is an image that is in some way applied to the geometry of a 3d model to add detail that otherwise would be too resource intensive to model. The misnomer lies in that the image gives the appearance of the object having texture but no actual relief is introduced. How the image is applied to the model is called texture mapping. So, again with the help of a modeling tool, the texture mapping for the pieces of the model was defined. After all this is done, the model is exported to an ascii file format, the geometry and texture mapping for each piece was extracted and placed into separate files that could be loaded by the application. Code has been written to read these files, read the texture files, and reconstruct the scene. Missing File (/dlc-2002/uploads/screen2.jpg) The reason we have gone to length in describing the process so far is to give an appreciation for what is involved in this task, and although it may not appear that much progress has been made, much work has been done. Also, although the bus stop model shown above has also been exported to VRML, through investigation it was found that the open source VRML reader being considered currently has a few serious bugs under the IRIX operating system - the ultimate target for the application. As this was unacceptable and all the features of VRML were not necessary, it was decided to write the scene loading/display code from the ground up. Another difficulty we have encountered in general is the "guinea pig" nature of our project with respect to student projects at the Visualization Center: editors not compiled, compilers not liscenced, permissions not set, machines being "basically disabled", scheduled time being cancelled with little or no notice. Up to this point, there have been three sessions at the vis center, only one of which (the most recent) being held in the CAVE and being mostly productive. The other two sessions were plagued by the problems mentioned above. On a more positive note though, at the moment the bus stop application runs in the CAVE... but the stop is as big as a city block, it is 20 feet above the viewer's head, and none of the textures appear correctly. These are actually relatively minor problems that should be fixed within another session or two. The group has plans to spend some time working at the Visualization Center over Spring Break. Looking Forward: We are currently investigating capturing the output of a web browser window and using that image as a texture within the busstop environment. This way, any interactive elements in the busstop may be designed as web pages for rapid development. We are also investigating the use of Python as a scripting language and how the Python interpreter can be interfaced with our application. With proper support from the Visualization Center, we may still be on target for producing a navigable and scriptable bus stop environment. Refernces and Resources: BP Center for Visualization Mobility for All Center for Lifelong Learning and Design Semester Design Project Home Pages
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