0031642: Visualization - crash in Graphic3d_Structure::SetVisual() on redisplaying...
[occt.git] / src / GeomAbs / GeomAbs_Shape.hxx
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42cf5bc1 1// Created on: 1993-02-22
2// Created by: Modelistation
3// Copyright (c) 1993-1999 Matra Datavision
4// Copyright (c) 1999-2014 OPEN CASCADE SAS
5//
6// This file is part of Open CASCADE Technology software library.
7//
8// This library is free software; you can redistribute it and/or modify it under
9// the terms of the GNU Lesser General Public License version 2.1 as published
10// by the Free Software Foundation, with special exception defined in the file
11// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
12// distribution for complete text of the license and disclaimer of any warranty.
13//
14// Alternatively, this file may be used under the terms of Open CASCADE
15// commercial license or contractual agreement.
16
17#ifndef _GeomAbs_Shape_HeaderFile
18#define _GeomAbs_Shape_HeaderFile
19
20
21//! Provides information about the continuity of a curve:
22//! - C0: only geometric continuity.
23//! - G1: for each point on the curve, the tangent vectors
24//! "on the right" and "on the left" are collinear with the same orientation.
25//! - C1: continuity of the first derivative. The "C1" curve is
26//! also "G1" but, in addition, the tangent vectors " on the
27//! right" and "on the left" are equal.
28//! - G2: for each point on the curve, the normalized
29//! normal vectors "on the right" and "on the left" are equal.
30//! - C2: continuity of the second derivative.
31//! - C3: continuity of the third derivative.
32//! - CN: continuity of the N-th derivative, whatever is the
33//! value given for N (infinite order of continuity).
34//! Also provides information about the continuity of a surface:
35//! - C0: only geometric continuity.
36//! - C1: continuity of the first derivatives; any
37//! isoparametric (in U or V) of a surface "C1" is also "C1".
38//! - G2: for BSpline curves only; "on the right" and "on the
39//! left" of a knot the computation of the "main curvature
40//! radii" and the "main directions" (when they exist) gives the same result.
41//! - C2: continuity of the second derivative.
42//! - C3: continuity of the third derivative.
43//! - CN: continuity of any N-th derivative, whatever is the
44//! value given for N (infinite order of continuity).
45//! We may also say that a surface is "Ci" in u, and "Cj" in v
46//! to indicate the continuity of its derivatives up to the order
47//! i in the u parametric direction, and j in the v parametric direction.
48enum GeomAbs_Shape
49{
50GeomAbs_C0,
51GeomAbs_G1,
52GeomAbs_C1,
53GeomAbs_G2,
54GeomAbs_C2,
55GeomAbs_C3,
56GeomAbs_CN
57};
58
59#endif // _GeomAbs_Shape_HeaderFile