Visualization of 3‐D computer‐aided design objects

Abstract

There are many significant human factors issues associated with the design and visualization of complex, computer‐generated images. One such issue is to determine the most effective techniques for providing engineers with realistic three‐dimensional (3‐D) objects. Differences in subjects’ ability to discriminate between the shape of two 3‐D, perspective, computer‐aided design‐type (CAD‐type) objects were investigated for various levels of monocular coding techniques and the binocular cue stereopsis. Performance was assessed at all combinations of five levels of monocular cues and two levels of disparity. The task was similar to the classic mental rotation paradigm except that subjects were provided with the ability to rotate one of the objects using a two‐dimensional (2‐D) joystick. Results indicate that interposition was the only depth cue that significantly enhanced subject performance. One explanation for the lack of significance of stereopsis is that, for this particular task, depth information provided by disparity was not needed. Detailed analysis of object rotation data using an orientation index (OI) suggests that subjects employed a feature‐by‐feature comparison task strategy. With tools that can evaluate cognitive activity such as the mental rotation paradigm and orientation index, researchers can learn more about how designers visualize and understand 3‐D CAD objects.