| 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; |