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    A New Algorithm of Space Tracing Using a CSG Model
    (Eurographics Association, 1987) Bouatouch, Kadi; Madani, M.O.; Priol, Thierry; Arnaldi, Bruno
    This paper describes a new algorithm of space tracing. Scenes are modeled by a CSG tree. Space is subdivided regularly into 3D regions called boxes. With each box is associated a subtree which is the restriction of the whole scene CSG tree to primitives belonging to this box. A 3D grid is used to access boxes.
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    Experimenting with a Parallel Ray-Tracing Algorithm on a Hypercube Machine
    (Eurographics Association, 1988) Priol, Thierry; Bouatouch, Kadi
    A parallel space tracing algorithm is presented. It subdivides the scene into regions. These latter are distributed among the processors of an iPSC hypercube machine designed by Intel company. Each processor subdivides its own region into cells to accelerate the ray tracing algorithm. Processors communicate by means of messages. The pyramidal shape of the regions allows the deletion of the primary ray messages. A method of performing a roughly uniform load distribution is proposed.
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    A VLSI Chip for Ray Tracing Bicubic Patches
    (Eurographics Association, 1989) Bouatouch, Kadi; Saouter, Yannick; Candela, Jean Charles
    This paper deals with the integration of a VLSI chip dedicated to ray tracing bicubic patches. A recursive subdivision algorithm is embedded in this chip. The recursion stops when the termination conditions are met. A software implementation allowed for the determination of key parameters which influenced the choice of the proposed chip' architecture. Only some modules of the chip are, at the present time, simulated and laid out, the rest is being implemented. A detailed description of the chip' modules is given.
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    Theoretical Developments on Polygonal Approximation of Parametric Surfaces for Ray Tracing
    (Blackwell Publishing Ltd and the Eurographics Association, 1988) Bouatouch, Kadi
    Some theoretical extensions are brought to Koparkar and Mudur s method which deals with a polygonal approximation of parametric surfaces using potential extrema. The proposed extensions allow the determination of both the existence and the equation of a curve solution of potential extrema. Solutions are given to solve the crack problem and to avoid the artificats due to an inexact ray-surface intersection point near the silhouette or on the higher curvature regions. Moreover, two methods of ray tracing surfaces are proposed.