No abstract available.

The use of true sculptured surface descriptions for design applications has been proposed by numerous authors. The actual implementation and use of interactive sculptured surface description techniques for design and production has been limited. The use of such techniques for ship hull design has been even more limited. The present paper describes a preliminary implementation of such a system for the design of ship hulls and for the production of towing tank models using numerical control techniques. The present implementation is based on a Cartesian product B-spline surface description. Implementation is on an Evans and Sutherland Picture System supported by a PDP-11/45 minicomputer.

This paper describes a stand alone graphics system utilizing a microprocessor based display controller with the capability of combining refresh with storage tube graphics. This combination is accomplished by utilizing the Write-Thru feature of a Tektronix 4014 display terminal. The display controller is a typical Z-80 microprocessor system interfaced to the 4014 by a standard Tektronix parallel interface. A portion of the Z-80 memory is used as the display buffer, allowing it to be divided into store and non-store (refreshed) segments. The microprocessor performs the conversion from the simple integer X, Y coordinates in the display buffer to actual Tektronix drawing commands. A second Z-80 microprocessor is used to perform graphical transformations and transfer the data from the PDP-11 host to the Z-80 display controller. The operations performed by the second microprocessor include translation, rotation and scaling. These operations are implemented by matrix multiplication of the user data by a user specified transformation matrix. The stand alone capabilities of the graphics system is made complete with interactive devices such as a tablet, analog dials, and function switches interfaced directly to the host computer.

This paper describes CAMILL, a system for computer aided milling of ship hull models defined with interactive graphics. The major hardware components of CAMILL are a mini-computer based refresh display and a three axis numerically controlled milling machine. For hardcopy documentation there is a large flatbed plotter. The two major software components are an interactive display program and a cutting program. The interactive display program is the human interface and provides capabilities for creating and modifying the ship design. The cutting program is executed in an intelligent terminal interfaced to the milling machine. The data used by the cutting program is generated by the display program and stored on a magnetic cassete tape. This cassette is transferred to the intelligent terminal for use by the cutting program. The main function of the cutting program is to direct the milling of the desired ship hull.