Described are improvements for the computer efficiency of the two midpoint scan-conversion algorithms used to draw ellipses. Included are computer programs written in C programing language. (JJK)

A proposition that 3-D CAD provides an array of unambiguous solutions to engineering problems is illustrated. This proposition assumes that engineering problems are conceived in parallel processing mode while they are solved in sequential processing mode. Circle construction analysis, parallel equidistant planes, and solid modeling are discussed.…

An approach to reduce the barrier between two-dimensional computer-aided drafting and three-dimensional constructive solids modeling is graphically illustrated. This process, or some derivative, encompasses a significant portion of the future direction for engineering graphics education. (KR)

The existing methods for graphically illustrating projection and coordinate systems for manual and computer-aided drafting and design are examined. Inconsistencies in methods used to graphically depict first and third angle projection in texts and the lack of attention in the relationship of projection to coordinate systems are noted. (KR)

An algorithm is described for generating smooth curves of first-order continuity. The algorithm is composed of several cubic Bezier curves joined together at the user defined control points. Introduced is a tension control parameter which can be set thus providing additional flexibility in the design of free-form curves. (KR)

Describes experiences for engineering students to develop spatial awareness and reasoning capability. Describes geometric modeling, basic geometric concepts, operations, surface modeling, and conclusions. (YP)

Presented is a proposed formula for determining the bearing angle and the slope angle for the line of intersection using the strike and dip angles of two given plane segments. Included is the development of the formula and three example problems. (KR)

Two graphics interface packages, PHIGS and HOOPS, are examined. A comparison of the two packages is made in light of the Iowa State University College of Engineering's need for educational software. Conclusions based on programing experience using both PHIGS and HOOPS are presented. (KR)

A software package which can aid descriptive geometry instruction is described. Included are the features of the software and the software configuration. This software has been honored as the best and most advanced software of its kind in the People's Republic of China. (KR)

An explanation of 3-D Computer Aided Design (CAD) usage to teach spatial geometry concepts using nontraditional techniques is presented. The software packages CADKEY and AutoCAD are described as well as their usefulness in solving space geometry problems. (KR)