Pssnap places a PostScript image of a geomview object in a file (default: snap.ps). Pssnap is meant to be run as a geomview external module, and draws the currently selected object from the point of view of the current camera.
The image is sized to fit on an 8.5 x 11 inch sheet of paper. Pssnap uses the orientation of the surfaces to determine lighting. When creating black and white PostScript, pssnap uses averages the r, g and b components of the color of the object using the formula
grey = .299 * r + .587 * g + .114 * b.
Pssnap does not support smooth shading. If an object contains per vertex colors, the entire face is given the same color as the first vertex.
Pssnap calls the same conversion routine as anytopl (see anytopl(3)) and so shares all its bugs.
Pssnap sorts the polygons by z value prior to drawing them instead of doing true z-buffering. This sometimes causes mistakes in the final image, particularly if the faces of the object intersect one another.
Celeste Fowler email: fowler@geom.umn.edu The Geometry Center phone: (612) 626-8304 1300 South Second Street Minneapolis, MN 55454