1. Abstract ESOLID is a computational geometry system that performs boundary evaluation using exact computation. Boundary Evaluation Exact computation Problem - the major problem is the inconsistency between input and output. Goals - Definition of a uniform and optimized file format to represent a geometric object along with an independent C++ module that utilizes the new format to write the geometry to the file and read it from the file. - Development of a routine that performs multiple boundary evaluations at once to facilitate the production of heavily detailed 3D objects. - Development of an extension to the current viewer in order to highlight important features (ex.patches). - current user interface only allows for one result to be generated from a single boolean operation, slowing the creation of highly detailed results. - the current visualiza- tion tool does not display helpful details about the solid (ex. patches). IN ESOLID OUT New I/O Module IN ESOLID OUT X - - List of Curves List of Patches List of Surfaces Segments List of Points List of Roots List of Polynomials Load/Save Module SOLID Sample of the XML output file ----------------------------------------------------------- SAVING THE SOLID TO AN XML FILE ----------------------------------------------------------- The solid data are arranged in a sequential manner following the hierarchy in the figure on the left. Then, it is printed in this order to an XML file. One thing to note about this format is that the lower the layer the bigger it is. The arrow from a block A to a block B means that the elements of A contain one or multiple references to one or several elements of B. ----------------------------------------------------------- LOADING THE SOLID FROM AN XML FILE ----------------------------------------------------------- The steps described above are performed backward. After, the XML file has been parsed, the hierarchy on the left is built, and the solid is generated from it. ----------------------------------------------------------- TESTING ----------------------------------------------------------- Comparison of the XML input and the current input. They are identical On the left, the union of a box and two ellipsoids. On the right, the difference of the box and the two ellipsoids. This test checks for consistency. The box is loaded into memory using the current input format whereas the two ellipsoids were loaded using the new XML format. Option User Interface(OUI)‏ The OUI is a simple way of using ESOLID by submitting an option or a sequence of options to a prompt. In other words, the interface is composed of the information to be manipulated, the list of possible options to choose, and a prompt awaiting the user input. The information to be manipulated is a list of solids displayed in the order they were loaded into memory A die modeled using the Option User Interface Automation... In general, the routine that automates a sequence of boolean operations reads a sequence file like the one above, parses it and performs the operations one at a time. Since ESOLID crashes whenever a degeneracy occurs, this routine saves the resulting solid of every operation and writes a backup file which is a sequence file starting with the result of the previous boolean operation. An example backup.xml file A crossed cube modeled using the automation routine Extending the viewer This was accomplished by implementing a random color generator that takes the number of patches as input and returns a list of random colors( size of list = number of patches ). This list of random colors is then passed to the visualization routine which will assign a random to a patch A crossed cube modeled using the automation routine E tending ESOLID X Gabriel Dzodom, John Keyser An exact boundary evaluation system