Spatial Navigation in Immersive Virtual Environments

Pedestrian movement studies in real environments have shown consistent statistical relationships between ‘configurational’ properties of spatial layouts and movement flows, facilitating prediction of movement from designs. However, these studies are at an aggregate level and say nothing about how individuals make the micro-scale decisions producing these emergent regularities. They do not therefore ‘explain’ movement. Progress on this is difficult since decision-making mechanisms are hard to observe in the real world and the ‘experimenter effect’ is ever-present. Could the study of movement in immersive virtual environments help? If it could be shown that movement in virtual environments was analogous to movement in real environments then microbehaviour data (head movement, direction of gaze, visual search behaviours) could be obtained through virtual experiments. The aim of this thesis is to explore this possibility by constructing experimental worlds with spatial properties varied to reflect those known to relate to movement in the real world, and asking individuals navigate through them immersively. Powerful analogies are initially demonstrated between virtual and real behaviour. Two types of micro-scale analysis are then performed: linear analysis, examining how routes are formed and how far linearity is conserved, using measurements of cumulative angular deviation along a path, string-matching algorithms to determine average routes, and analysis of isovist attributes along routes; and positional analysis, focussing upon pausing behaviour, including examining where subjects pause along routes, what choices are made at junctions, how isovist properties of pauselocations compare with an environment’s overall isovist attribute distribution, and correlating pause-point and isovist data. In each analysis, ‘subjective’ movement behaviour is related to ‘objective’ properties of environments. The experiments show results strongly suggesting how noted aggregate regularities are produced: linearity is strongly conserved, usually following long sight-lines, with pauses in configurationally ‘integrated’ locations offering strategic visual properties, long lines of sight, and large isovist areas

Perspective in Two Dimensions for Computer Graphics

Computer graphics perspective is based on photography, the pin-hole camera model. This thesis examines the perspective as practiced by artists, who develop the picture geometry within the planar surface of the canvas. Their approach is flexible, depth is simulated with planar composition as the primary geometry. Renaissance artists discovered construction methods to draw the foreshortening of realistic pictures: the construction of a tiled floor in perspective was fundamental. This thesis presents the framework, a computer program, I developed to create the perspective of pictures based on the geometry practices of artists. Construction lines on the image plane simulate the 3D geometry of the pictorial space; cartoons of foreground elements are manipulated in 2D within the picture perspective; projected shadows, examples of double projection, are also included. A formalism, reformulating algebraically the straight-edge and compass evaluations, generalizes the planar geometry that solves the challenge of depicting 3D. A revised Painter’s algorithm produces the occlusions between the picture elements from sequencing them from their definitions on the canvas

Fourth Annual Workshop on Space Operations Applications and Research (SOAR 90)

The proceedings of the SOAR workshop are presented. The technical areas included are as follows: Automation and Robotics; Environmental Interactions; Human Factors; Intelligent Systems; and Life Sciences. NASA and Air Force programmatic overviews and panel sessions were also held in each technical area

First International Symposium on Strain Gauge Balances

The first International Symposium on Strain Gauge Balances was sponsored and held at NASA Langley Research Center during October 22-25, 1996. The symposium provided an open international forum for presentation, discussion, and exchange of technical information among wind tunnel test technique specialists and strain gauge balance designers. The Symposium also served to initiate organized professional activities among the participating and relevant international technical communities. Over 130 delegates from 15 countries were in attendance. The program opened with a panel discussion, followed by technical paper sessions, and guided tours of the National Transonic Facility (NTF) wind tunnel, a local commercial balance fabrication facility, and the LaRC balance calibration laboratory. The opening panel discussion addressed "Future Trends in Balance Development and Applications." Forty-six technical papers were presented in 11 technical sessions covering the following areas: calibration, automatic calibration, data reduction, facility reports, design, accuracy and uncertainty analysis, strain gauges, instrumentation, balance design, thermal effects, finite element analysis, applications, and special balances. At the conclusion of the Symposium, a steering committee representing most of the nations and several U.S. organizations attending the Symposium was established to initiate planning for a second international balance symposium, to be held in 1999 in the UK