Modeling Algorithms

Modeling Algorithms containing a vast range of geometrical and topological algorithms.


Modeling Algorithms module groups a wide range of topological and geometric algorithms used in geometric modeling. Basically, there are two groups of algorithms in Open CASCADE Technology:

  • High-level modeling routines used in the real design;
  • Low-level mathematical support functions used as a groundwork for the modeling API;
  • Low-level geometric tools provide the algorithms, which:
    • Calculate the intersection of two curves, surfaces, or a curve and a surface;
    • Project points onto 2D and 3D curves, points onto surfaces and 3D curves onto surfaces;
    • Construct lines and circles from constraints;
    • Construct free-form curves and surfaces from constraints (interpolation, approximation, skinning, gap filling, etc);
  • Low-level topological tools provide the algorithms, which:
    • Tessellate shapes;
    • Check correct definition of shapes;
    • Determine the local and global properties of shapes (derivatives, mass-inertia properties, etc);
    • Perform affine transformations;
    • Find planes in which edges are located;
    • Convert shapes to NURBS geometry;
    • Sew connected topologies (shells and wires) from separate topological elements (faces and edges).

Top-level API provides the following functionality:

  • Construction of Primitives:
    • Boxes;
    • Prisms;
    • Cylinders;
    • Cones;
    • Spheres;
    • Toruses.
  • Kinematic Modeling:
    • Prisms - linear sweeps;
    • Revolutions - rotational sweeps;
    • Pipes - general-form sweeps;
    • Lofting.

Shapes containing pipes with variable radius produced by sweeping

  • Boolean Operations, which allow creating new shapes from the combinations of source shapes. For two shapes S1 and S2:
    • Common contains all points that are in S1 and S2;
    • Fuse contains all points that are in S1 or S2;
    • Cut contains all points in that are in S1 and not in S2.

    See Boolean Operations User's Guide for detailed documentation.

  • Algorithms for local modifications such as:
    • Hollowing;
    • Shelling;
    • Creation of tapered shapes using draft angles;
    • Algorithms to make fillets and chamfers on shape edges, including those with variable radius (chord).
  • Algorithms for creation of mechanical features, i.e. depressions, protrusions, ribs and grooves or slots along planar or revolution surfaces.

Please, see the details in Modeling Algorithms User's Guide.

See also: E-learning & Training.