Jan Helge Bøhn

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Most of the work accomplished on surface blending is based on visual trimming. In the process of visual trimming, the unwanted portion of a surface is only hidden but not removed. Geometric trimming provides a complete mathematical description of the wanted portion of the trimming surface, and generates a new mathematical surface or sets of surface patches.(More)
STEP, or ISO 10303, is a unique and innovative solution to the problem of product data representation and communication. This paper focuses on information modeling in STEP. The data description language EXPRESS is presented, along with a discussion on the modeling of information rather than just data. The process for the construction of Integrated Resources(More)
Existing layered manufacturing systems fabricate parts using a constant build layer thickness. Hence, operators must compromise between rapid production with large surface inaccuracies, and slow production with high precision, by choosing between thick and thin build layers, respectively. Adaptive layered manufacturing methods alleviate this decision by(More)
An inexpensive device was created for computed tomographic (CT)-guided stereotactic biopsy of the canine brain. The accuracy of the device was tested using 16, formalin-perfused, canine head specimens. For each dog, a 6-inch biopsy needle was guided into pituitary gland and caudate nucleus targets. Needle tracks were measured using the CT computer and(More)
NURBS, Non-Uniform Rational B-splines, is a widely accepted standard tool for geometry representation and design. The two major components of NURBS Ñ Rational and B-splines Ñ need to be understood in order to have a fair understanding of NURBS. In this paper, an attempt is made to present the concept of B-splines curves and surfaces and introduce NURBS(More)