Abstract: A curve projected onto a NURBS surface defines trim regions on the NURBS surface. A plurality of spaced-apart points are defined on the curve and rays are project through the points toward a NURBS surface. Any intersections of the rays with the NURBS surface is mapped into the U,V domain. Corresponding points of adjacent rays are connected to define at least a portion of each trim region on the NURBS surface. Transitions on the NURBS surface between adjacent rays are detected based upon differences in the number of intersections of adjacent rays. The location of each transition is determined to within a selected tolerance by using a binary subdivision of the interval between adjacent rays. The location of such transitions is used to determine how intersections of the rays with the surface at the boundaries of the NURBS surface should be connected. Parity assigned to the rays at each intersection determines the direction in which intersections along the rays are connected.

Abstract: Electrophotographic method of obtaining lithographic printing plates comprising the following steps: (i) uniformly electrostatically charging a photoconductor element, (ii) image-wise discharging said photoconductor element, (iii) developing the resulting electrostatic charge pattern with dry toner particles of which more than 90% by volume have an equivalent particle size diameter less than 10 microns and more than 50% by volume have an equivalent particle size diameter less than 7 microns, (iv) electrostatically transferring the developed image to a toner receiving plate, said toner receiving plate comprising a plastic film support that is thermostable to a temperature of at least 140.degree. C. and a crosslinked hydrophilic layer thereon, said layer containing infrared absorbing substances in such an amount that the reflection density of said layer in the visible spectrum is between 0.4 and 1.4, and (v) fixing the transferred toner to said toner receiving plate by infrared radiation fusing.

Abstract: A process of making biaxially oriented polyethylene terephthalate photographic film having a controlled amount of curl in the longitudinal direction, wherein the file is subjected to longitudinal stretching while being asymmetrically heated across its thickness, then wound into a stock roll, and the stock roll thus obtained is heat-tempered. The stock roll after heat-tempering may be longitudinally slit, cut and rewound into smaller rolls in a winding direction opposite to the direction of the longitudinal curl induced in the film during the longitudinal asymmetrical heat-stretching.