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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; |