Research Projects

Intelligent Reuse of CAD models and Manufacturing Plans

ABSTRACT In this research work an Automated Process Planning system that utilizes the advantages of both variant and generative process planning is developed. Plan reuse is an essential part in manufacturing industries. By retrieving a similar process plan and adapting it to fit to a new part reduces the lead times for manufacturing. In this work a system is developed which accepts a 3D prismatic solid model as a boundary representation (brep) file. Features (such as slot, step, pocket, hole, blind-step and blind-slot) and their interactions with each other are retrieved from this solid model and are used to represent the part. The features and the interactions together are used to find similar parts from the database by relaxing some properties if required. The retrieved parts are then ranked by similarity. The process plan of the most similar part is used to adapt to the new part. If no similar part is obtained then the process plan for the new part is developed using knowledge of process planning. The process plan is then verified by simulation. And finally both the part and it's modified process plan are stored in the database for future use. By using this strategy the system learns from its previous experience. IMPLEMENTATION Implemented in Python. I am still working on it. Click here to access the page (Requires authentication, not open to public)

An Interactive Multi-User System for Simultaneous Graph Drawing

ABSTRACT In this research we consider the problem of simultaneous drawing of two graphs. The goal is to produce aesthetically pleasing drawings for the two graphs by means of a heuristic algorithm and with human assistance. Our implementation uses the DiamondTouch table, a multi- user, touch-sensitive input device, to take advantage of direct physical interaction of several users working collaboratively We present an interactive multi-user system for simultaneous graph drawing. The system uses the DiamondTouch table, and allows for collaborative work of up to four users. We also provide a heuristic algorithm that attempts to minimize the number of crossings. The algorithms can be used on the entire graphs or on subsets of nodes. The users can stop the algorithm, move nodes around and restart it with the updated positions. Thus, the users can help the algorithm move out of a local minimum, or guide the algorithm towards a more aesthetically appealing solution. Alternatively, if the users get stuck in a local minimum, the algorithm can be started from a random position that may lead to a better solution. Finally, our system works not only with the DiamondTouch table, but also as a Java desktop application, or as a Java applet. IMPLEMENTATION An Implementation of this system as an applet can be found at http://www.ece.arizona.edu/~chandanp/research/sgd/ http://dt.cs.arizona.edu/sgd/sgd.html PAPER /PUBLICATION Download the .pdf file here or obtain it from CS Department here Submitted to Graph Drawing 2004 [Awaiting Selection] IMAGE GALLERY Click here to visit the image gallery (If the previous link does not work click here)

Intersection-Free Morphing of Planar Graphs

ABSTRACT Morphing refers to the process of transforming one shape (the source) into another (the target). Morphing is widely used in computer graphics, animation, and modeling. In planar graph morphing we would like to transform a given source graph to another pre-specified target graph. A smooth transformation of one graph into another can be useful for numerous problems from graph drawing. In particular, when dealing with dynamic graphs and graphs that change through time, it is crucial to preserve the mental map of the user. Thus, it is important to minimize the changes to the drawing and to create a smooth transition between consecutive drawings. Another important goal is to avoid creating any intersections throughout the morph. We designed and implemented an algorithm that can morph between drawings with straight-line segments, bends and it relies on a combination of techniques to achieve smooth transformations: rigid morphing, compatible triangulations, as well as morphing based on interpolation of the convex representations of the graphs. For example given the two layouts on the left(top-left is the source, bottom-right drawn opaquely is the target layout) we are interested in finding a smooth sequence of layouts starting from the source ending with the target layout. We want each intermediate layout in the sequence contain no edge-crossings. Our algorithm has 4 main parts: Apply Rigid motion on source layout Introduce necessary bends Compatibly triangulate the two layouts Morph using convex representations IMPLEMENTATION An Implementation of this system as an applet can be found at http://www.ece.arizona.edu/~chandanp/research/gmorph/ http://gmorph.cs.arizona.edu/morphing.html PAPER /PUBLICATION Here is a Video demo ( Anonymous ftp Download, http Download avi format, http Download mpeg format). You can download the necessary codec at TechSmith Screen Capture Codec. Download the .pdf file here or obtain it from CS Department here Chandan Pitta, Cesim Erten and Stephen G. Kobourov, "Morphing Planar Graphs", 20th Annual Symposium on Computational Geometry (SCG), to appear in 2004 Chandan Pitta, Cesim Erten and Stephen G. Kobourov, "Intersection-Free Morphing of Planar Graphs", 11th Symposium on Graph Drawing (GD), p. 320-331, 2003. MOVIE GALLERY Click here to visit the movie gallery (If the previous link does not work click here)