Extensions to OpenGL for CAGD.

Many computer graphic API’s, including OpenGL, emphasize modeling with rectangular patches, which are especially useful in Computer Aided Geomeric Design (CAGD). However, not all shapes are rectangular; some are triangular or more complex. This paper extends the OpenGL library to support the modeling of triangular patches, Coons patches, and Box-splines patches. Compared with the triangular patch created from degenerate rectangular Bezier patch with the existing functions provided by OpenGL, the triangular Bezier patches can be used in certain design situations and allow designers to achieve high-quality results that are less CPU intense and require less storage space. The addition of Coons patches and Box splines to the OpenGL library also give it more functionality. Both patch types give CAGD users more flexibility in designing surfaces. A library for all three patch types was developed as an addition to OpenGL

Automated Design of a High-Velocity Channel

Engineering design is a decision-making process. Optimization techniques can be used to insure that better decisions are made. One design of great interest to engineers is that of high-velocity channels used for routing floodwater out of urban areas. In the design of these channels it is very important to avoid such hydraulic phenomena as standing waves, hydraulic jumps, and shocks. These will require higher wall heights and more expense. These channels can be modeled with physical models, but they are expensive and time consuming. To minimize the cost of building and changing the physical models and the time required to perform the study, an automated numerical model can be used to test a range of designs before construction of the physical model. The resulting design can be used as an initial design, which is close to the desired design requiring fewer changes to the physical model, saving time and money