Main geometry types used for solid models

5 main geometry types

  • NURBS (boundary representation)
    • Spline based description of the surfaces enclosing the volume. NURBS can be used to represent basic algebraic shapes as well as freeform shapes, such as car bodies
  • Sub divisions polygon, subD (boundary representation)
    • Polygon (mesh) based description of the surfaces enclosing the volume. The main, coarse, control mesh is automatically divided into a smother, sub divided final mesh by the CAD tool. SubD is well suited for modeling advanced freeform shapes
  • T-splines (boundary representation
    • NURBS-based but behaves like subD - easy to convert to NURBS
  • Constructive solid geometry (CSG) (direct volume representation)
    • Constructive boolean operations on algebraic primitives (volumes), like cones, cylinders, boxes, ...
  • Voxels (direct volume representation)
    • The solid is represented by a number of smaller 3D boxes (volumes). Like building with LEGO. A voxel may contain information such as density, doppler data, time ...
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