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1 | -- File: TopTrans.cdl |

2 | -- Created: Mon Oct 28 14:59:09 1991 |

3 | -- Author: Remi LEQUETTE |

4 | -- <rle@phobox> |

5 | ---Copyright: Matra Datavision 1991, 1992 |

6 | |

7 | |

8 | package TopTrans |

9 | |

10 | ---Purpose: This package provides algorithms to compute |

11 | -- complex transitions. A transition is the status of |

12 | -- geometry near the boundary of a Shape. An example |

13 | -- is the intersection of a curve and a surface |

14 | -- enclosing a solid , the transition tells if the |

15 | -- parts of the curve just before and just after the |

16 | -- intersection are inside, outside or on the |

17 | -- boundary of the solid. |

18 | -- |

19 | -- The difficulty with transitions arise when dealing |

20 | -- with trimmed geometries like edges and faces. When |

21 | -- the geometric intersections are inside the trimmed |

22 | -- geometry the transition is usually computed by the |

23 | -- intersection algorithms as the trimming can be |

24 | -- safely ignored. If the intersection falls on the |

25 | -- trimming boundaries one must consider the |

26 | -- neighbouring entities. Consider as an example the |

27 | -- intersection of a curve and a solid, if the |

28 | -- intersection falls on an edge of the solid it does |

29 | -- not falls inside the two faces adjacent to the |

30 | -- edge, a complex transition occurs. |

31 | -- |

32 | -- This package provides two classes : |

33 | -- |

34 | -- * CurveTransition is used to compute complex |

35 | -- transitions with an other curve. |

36 | -- |

37 | -- * SurfaceTransition is used to compute complex |

38 | -- transitions in 3D space. |

39 | -- |

40 | -- The curves and surfaces are given by a first or |

41 | -- second order approximation around the intersection |

42 | -- point. For a curve, the tangent vector or the |

43 | -- osculating circle. For a surface the normal vector |

44 | -- or the osculating quadric. |

45 | |

46 | uses |

47 | Standard, |

48 | TCollection, |

49 | TColStd, |

50 | gp, |

51 | TopAbs |

52 | |

53 | is |

54 | |

55 | class Array2OfOrientation instantiates |

56 | Array2 from TCollection (Orientation from TopAbs); |

57 | |

58 | class CurveTransition; |

59 | |

60 | class SurfaceTransition; |

61 | |

62 | end TopTrans; |