A DESIGN AND INTERROGATION SYSTEM FOR MODELLING WITH RATIONAL B-SPLINES

The creation and evaluation of free-form curves and surfaces defined in terms of non-uniform rational B-splines is important for computer-aided geometric modelling of many marine structures. The paper outlines methods allowing creation of such curves and surfaces, focusing on methods which allow evaluation of their smoothness and character. Evaluation of curves is performed through curvature maps. Evaluation of surfaces includes wire frame and shaded image visualisations, sectioning through appropriate algebraic surfaces such as planes and cylinders, isophotes, reflection lines, orthotomics, Gaussian, mean, absolute principal and directional curvature maps and curvature lines. This is followed by a description of automated curve and surface fairing methods. Such procedures perform shape modifications to achieve smoother and less oscillatory forms. An executive system which allows creation, editing, interrogation and fairing of B-spline curves and surface patches is described. Examples from the application of the above system in shape interrogation and fairing of marine structures are given.

• Supplemental Notes:
  • Proc 9th Intl Conference Offshore Mechanics & Arctic Engng, 1990, v 1, pt B, p 555 [11 p, 35 ref, 12 fig]
• Authors:
  • Alourdas, P G
  • Hottel, G
  • Tuohy, S T
• Publication Date: 1990

Language

• English

Subject/Index Terms

• TRT Terms: Computer aided design; Fairing lines
• Old TRIS Terms: Curved shapes; Lines fairing
• Subject Areas: Design; Marine Transportation;

Filing Info

• Accession Number: 00699214
• Record Type: Publication
• Source Agency: British Maritime Technology
• Files: TRIS
• Created Date: Aug 14 1995 12:00AM