[occt.git] / src / Geom / Geom_OffsetCurve.cdl

-- Created on: 1993-03-10
-- Created by: JCV
-- Copyright (c) 1993-1999 Matra Datavision
-- Copyright (c) 1999-2012 OPEN CASCADE SAS
--
-- The content of this file is subject to the Open CASCADE Technology Public
-- License Version 6.5 (the "License"). You may not use the content of this file
-- except in compliance with the License. Please obtain a copy of the License
-- at http://www.opencascade.org and read it completely before using this file.
--
-- The Initial Developer of the Original Code is Open CASCADE S.A.S., having its
-- main offices at: 1, place des Freres Montgolfier, 78280 Guyancourt, France.
--
-- The Original Code and all software distributed under the License is
-- distributed on an "AS IS" basis, without warranty of any kind, and the
-- Initial Developer hereby disclaims all such warranties, including without
-- limitation, any warranties of merchantability, fitness for a particular
-- purpose or non-infringement. Please see the License for the specific terms
-- and conditions governing the rights and limitations under the License.


class OffsetCurve from Geom inherits Curve from Geom

    
        ---Purpose :
        --  This class implements the basis services for an offset curve
        --  in 3D space. The Offset curve in this package can be a self
        --  intersecting curve even if the basis curve does not 
        --  self-intersect. The self intersecting portions are not deleted
        --  at the construction time.
        --  An offset curve is a curve at constant distance (Offset) from
        --  a basis curve in a reference direction V. The offset curve 
        --  takes its parametrization from the basis curve.
        --  The Offset curve is in the direction of the normal N 
        --  defined with the cross product  T^V, where the vector T
        --  is given by the first derivative on the basis curve with 
        --  non zero length.
        --  The distance offset may be positive or negative to indicate the
        --  preferred side of the curve :
        --  . distance offset >0 => the curve is in the direction of N
        --  . distance offset <0 => the curve is in the direction of - N
        --  
        --  On the Offset curve :
        --  Value (U) = BasisCurve.Value(U) + (Offset * (T ^ V)) / ||T ^ V||
        --  
        --  At any point the Offset direction V must not be parallel to the
        --  vector T and the vector T must not have null length else the
        --  offset curve is not defined. So the offset curve has not the 
        --  same continuity as the basis curve.
        -- 
        --   Warnings :
        --  
        --  In this package we suppose that the continuity of the offset
        --  curve is one degree less than the continuity of the basis 
        --  curve and we don't check that at any point ||T^V|| != 0.0
        --  
        --  So to evaluate the curve it is better to check that the offset
        --  curve is well defined at any point because an exception could 
        --  be raised. The check is not done in this package at the creation
        --  of the offset curve because the control needs the use of an
        --  algorithm which cannot be implemented in this package.
        -- 
        --  The OffsetCurve is closed if the first point and the last point
        --  are the same (The distance between these two points is lower or
        --  equal to the Resolution sea package gp) . The OffsetCurve can be
        --  closed even if the basis curve is not closed. 


uses Dir      from gp,
     Pnt      from gp,
     Trsf     from gp,
     Vec      from gp,
     Curve    from Geom,
     Geometry from Geom,
     Shape    from GeomAbs


raises ConstructionError   from Standard,
       RangeError          from Standard,
       NoSuchObject        from Standard,
       UndefinedDerivative from Geom,
       UndefinedValue      from Geom


is


  Create (C : Curve from Geom; Offset : Real;  V : Dir)
     returns mutable OffsetCurve
        ---Purpose :
        --  C is the basis curve, Offset is the distance between <me> and
        --  the basis curve at any point. V defines the fixed reference 
        --  direction (offset direction). If P is a point on the basis
        --  curve and T the first derivative with non zero length
        --  at this point, the corresponding point on the offset curve is
        --  in the direction of the vector-product N = V ^ T   where
        --  N is a unitary vector.
        --  Warnings :
        --  In this package the entities are not shared. The OffsetCurve is
        --  built with a copy of the curve C. So when C is modified the
        --  OffsetCurve is not modified
     raises ConstructionError;
        ---Purpose :
        --  Raised if the basis curve C is not at least C1.
        --  Warnings :
        --  No check is done to know if ||V^T|| != 0.0 at any point.
        

  Reverse (me : mutable);
        ---Purpose  : Changes the orientation of this offset curve.
    	-- As a result:
    	-- - the basis curve is reversed,
    	-- - the start point of the initial curve becomes the
    	--   end point of the reversed curve,
    	-- - the end point of the initial curve becomes the
    	--   start point of the reversed curve, and
    	-- - the first and last parameters are recomputed.
  

  ReversedParameter(me; U : Real) returns Real;
	---Purpose: Computes the parameter on the reversed curve for
    	-- the point of parameter U on this offset curve.
 

  SetBasisCurve (me : mutable; C : Curve from Geom)
     raises ConstructionError;
        ---Purpose :  Changes this offset curve by assigning C as the basis curve from which it is built.
    	-- Exceptions
    	-- Standard_ConstructionError if the curve C is not at least "C1" continuous.
      

  SetDirection (me : mutable; V : Dir);
    	---Purpose : Changes this offset curve by assigning V as the
    	-- reference vector used to compute the offset direction.

  SetOffsetValue (me : mutable; D : Real);
        ---Purpose :  Changes this offset curve by assigning D as the offset value.


  BasisCurve (me) returns Curve from Geom;
    	---Purpose : Returns the basis curve of this offset curve.
    	-- Note: The basis curve can be an offset curve.


  Continuity (me)  returns Shape from GeomAbs;
    	---Purpose : Returns the global continuity of this offset curve as a
    	-- value of the GeomAbs_Shape enumeration.
    	-- The degree of continuity of this offset curve is equal
    	-- to the degree of continuity of the basis curve minus 1.
        --  Continuity of the Offset curve :
        --  C0 : only geometric continuity,
        --  C1 : continuity of the first derivative all along the Curve,
        --  C2 : continuity of the second derivative all along the Curve,
        --  C3 : continuity of the third derivative all along the Curve,
        --  G1 : tangency continuity all along the Curve,
        --  G2 : curvature continuity all along the Curve,
        --  CN : the order of continuity is infinite.
        --  Warnings :
        --  Returns the continuity of the basis curve - 1. 
        --  The offset curve must have a unique offset direction defined
        --  at any point.


  Direction (me)  returns Dir;
        ---Purpose : Returns the reference vector of this offset curve.
     	---C++: return const&
   
        ---Purpose  : Value and derivatives
        --  Warnings :
        --  The exception UndefinedValue or UndefinedDerivative is 
        --  raised if it is not possible to compute a unique offset
        --  direction.
        --  If T is the first derivative with not null length and
        --  V the offset direction the relation ||T(U) ^ V|| != 0
        --  must be satisfied to evaluate the offset curve.
        --  No check is done at the creation time and we suppose
        --  in this package that the offset curve is well defined.


  D0(me; U : Real; P : out Pnt);
        ---Purpose:  Warning! this should not be called 
        --          if the basis curve is not at least C1. Nevertheless
        --          if used on portion where the curve is C1, it is OK


  D1 (me; U : Real; P : out Pnt; V1 : out Vec)
     raises UndefinedDerivative;
        ---Purpose:  Warning! this should not be called 
        --           if the continuity of the basis curve is not C2.
        --           Nevertheless, it's OK to use it  on portion 
        --           where the curve is C2


  D2 (me; U : Real; P : out Pnt; V1, V2 : out Vec)
     raises UndefinedDerivative;
        ---Purpose:  Warning! this should not be called 
        --           if the continuity of the basis curve is not C3.
        --           Nevertheless, it's OK to use it  on portion 
        --           where the curve is C3  
       

  D3 (me; U : Real; P : out Pnt; V1, V2, V3 : out Vec)
     raises UndefinedDerivative;
     	---Warning:
        --         this should not be called 
        --           if the continuity of the basis curve is not C4.
        --           Nevertheless, it's OK to use it  on portion 
        --           where the curve is C4  
       

  DN (me; U : Real; N : Integer)   returns Vec
        ---Purpose :
        --  The returned vector gives the value of the derivative
        --  for the order of derivation N.    
     	--Warning!
        --         this should not be called 
        --           if the continuity of the basis curve is not CN+1.
        --           Nevertheless, it's OK to use it  on portion 
        --           where the curve is CN+1  
       
     raises UndefinedDerivative,


        ---Purpose  : 
        --  The following functions compute the value and derivatives
        --  on the offset curve and returns the derivatives on the
        --  basis curve too.  
        --  The computation of the value and derivatives on the basis
        --  curve are used to evaluate the offset curve
        --  
        --  Warning:
        --  The exception UndefinedValue or UndefinedDerivative is 
        --  raised if it is not possible to compute a unique offset
        --  direction.
    
    	    RangeError;
        ---Purpose : Raised if N < 1.
        --         

  Value (me; U : Real; P, Pbasis : out Pnt; V1basis : out Vec)
     raises UndefinedValue;

    	---Purpose:  Warning! this should not be called 
        --          if the basis curve is not at least C1. Nevertheless
        --          if used on portion where the curve is C1, it is OK 
  
  D0 (me; U : Real; P, Pbasis : out Pnt; V1basis : out Vec)
     raises UndefinedValue;
     	---Purpose:  Warning! this should not be called 
        --           if the continuity of the basis curve is not C1.
        --           Nevertheless, it's OK to use it  on portion 
        --           where the curve is C1

  
  D1 (me; U : Real; P, Pbasis : out Pnt; V1, V1basis, V2basis : out Vec)
     raises UndefinedDerivative;
        ---Purpose:  Warning! this should not be called 
        --           if the continuity of the basis curve is not C1.
        --           Nevertheless, it's OK to use it  on portion 
        --           where the curve is C1

  D2 (me; U : Real; P, Pbasis : out Pnt;  V1, V2, V1basis, V2basis, 
      V3basis : out Vec)
     raises UndefinedDerivative;

    	---Purpose:  Warning!  this should not be called 
        --           if the continuity of the basis curve is not C3.
        --           Nevertheless, it's OK to use it  on portion 
        --           where the curve is C3  
  FirstParameter (me)  returns Real;

  LastParameter (me)   returns Real;

    	--- Purpose: Returns the value of the first or last parameter of this
    	-- offset curve. The first parameter corresponds to the
    	-- start point of the curve. The last parameter
    	-- corresponds to the end point.
    	-- Note: the first and last parameters of this offset curve
    	-- are also the ones of its basis curve.
    
  Offset (me)          returns Real;
    	---Purpose: Returns the offset value of this offset curve.
    
  IsClosed (me)   returns Boolean;
        ---Purpose : Returns True if the distance between the start point 
        --  and the end point of the curve is lower or equal to 
        --  Resolution from package gp.


  IsCN (me; N : Integer)  returns Boolean
        ---Purpose : Returns true if the degree of continuity of the basis
    	-- curve of this offset curve is at least N + 1.
        --  This method answer True if the continuity of the basis curve 
        --  is N + 1.  We suppose in this class that a normal direction
        --  to the basis curve (used to compute the offset curve) is 
        --  defined at any point on the basis curve.
     raises RangeError;
        ---Purpose : Raised if N < 0.


  IsPeriodic (me)  returns Boolean;
    	---Purpose : Returns true if this offset curve is periodic, i.e. if the
    	-- basis curve of this offset curve is periodic.


  Period (me) returns Real from Standard
	---Purpose: Returns the period of this offset curve, i.e. the period
    	-- of the basis curve of this offset curve.
    	-- Exceptions
    	-- Standard_NoSuchObject if the basis curve is not periodic.
  raises
    	NoSuchObject from Standard
  is redefined;


  Transform (me : mutable; T : Trsf);
        --- Purpose: Applies the transformation T to this offset curve.
    	-- Note: the basis curve is also modified.

  TransformedParameter(me; U : Real; T : Trsf from gp) returns Real
    	---Purpose: Returns the  parameter on the  transformed  curve for
    	--       the transform of the point of parameter U on <me>.
    	--      me->Transformed(T)->Value(me->TransformedParameter(U,T))
	--          is the same point as
	--          me->Value(U).Transformed(T)
	--          This methods calls the basis curve method.
     is redefined;  

  ParametricTransformation(me; T : Trsf from gp) returns Real
    	---Purpose: Returns a  coefficient to compute the parameter on
    	--          the transformed  curve  for  the transform  of the
	--          point on <me>.
	--          
    	--          Transformed(T)->Value(U * ParametricTransformation(T))
	--          is the same point as
	--          Value(U).Transformed(T)
	--          This methods calls the basis curve method.
     is redefined;  

	     
  Copy (me)  returns mutable like me;
    	---Purpose: Creates a new object which is a copy of this offset curve.

fields

  basisCurve  : Curve from Geom;
  direction   : Dir;
  offsetValue : Real;

end;
Commit	Line	Data
b311480e	1	-- Created on: 1993-03-10
	2	-- Created by: JCV
	3	-- Copyright (c) 1993-1999 Matra Datavision
	4	-- Copyright (c) 1999-2012 OPEN CASCADE SAS
	5	--
	6	-- The content of this file is subject to the Open CASCADE Technology Public
	7	-- License Version 6.5 (the "License"). You may not use the content of this file
	8	-- except in compliance with the License. Please obtain a copy of the License
	9	-- at http://www.opencascade.org and read it completely before using this file.
	10	--
	11	-- The Initial Developer of the Original Code is Open CASCADE S.A.S., having its
	12	-- main offices at: 1, place des Freres Montgolfier, 78280 Guyancourt, France.
	13	--
	14	-- The Original Code and all software distributed under the License is
	15	-- distributed on an "AS IS" basis, without warranty of any kind, and the
	16	-- Initial Developer hereby disclaims all such warranties, including without
	17	-- limitation, any warranties of merchantability, fitness for a particular
	18	-- purpose or non-infringement. Please see the License for the specific terms
	19	-- and conditions governing the rights and limitations under the License.
	20
7fd59977	21
	22
	23	class OffsetCurve from Geom inherits Curve from Geom
	24
	25
	26	---Purpose :
	27	-- This class implements the basis services for an offset curve
	28	-- in 3D space. The Offset curve in this package can be a self
	29	-- intersecting curve even if the basis curve does not
	30	-- self-intersect. The self intersecting portions are not deleted
	31	-- at the construction time.
	32	-- An offset curve is a curve at constant distance (Offset) from
	33	-- a basis curve in a reference direction V. The offset curve
	34	-- takes its parametrization from the basis curve.
9733d9b3	35	-- The Offset curve is in the direction of the normal N
9733d9b3	36	-- defined with the cross product T^V, where the vector T
7fd59977	37	-- is given by the first derivative on the basis curve with
	38	-- non zero length.
	39	-- The distance offset may be positive or negative to indicate the
	40	-- preferred side of the curve :
	41	-- . distance offset >0 => the curve is in the direction of N
9733d9b3	42	-- . distance offset <0 => the curve is in the direction of - N
7fd59977	43	--
	44	-- On the Offset curve :
	45	-- Value (U) = BasisCurve.Value(U) + (Offset * (T ^ V)) / \|\|T ^ V\|\|
	46	--
	47	-- At any point the Offset direction V must not be parallel to the
	48	-- vector T and the vector T must not have null length else the
	49	-- offset curve is not defined. So the offset curve has not the
	50	-- same continuity as the basis curve.
	51	--
	52	-- Warnings :
	53	--
	54	-- In this package we suppose that the continuity of the offset
	55	-- curve is one degree less than the continuity of the basis
	56	-- curve and we don't check that at any point \|\|T^V\|\| != 0.0
	57	--
	58	-- So to evaluate the curve it is better to check that the offset
	59	-- curve is well defined at any point because an exception could
	60	-- be raised. The check is not done in this package at the creation
	61	-- of the offset curve because the control needs the use of an
	62	-- algorithm which cannot be implemented in this package.
	63	--
	64	-- The OffsetCurve is closed if the first point and the last point
	65	-- are the same (The distance between these two points is lower or
	66	-- equal to the Resolution sea package gp) . The OffsetCurve can be
	67	-- closed even if the basis curve is not closed.
	68
	69
	70	uses Dir from gp,
	71	Pnt from gp,
	72	Trsf from gp,
	73	Vec from gp,
	74	Curve from Geom,
	75	Geometry from Geom,
	76	Shape from GeomAbs
	77
	78
	79	raises ConstructionError from Standard,
	80	RangeError from Standard,
	81	NoSuchObject from Standard,
	82	UndefinedDerivative from Geom,
	83	UndefinedValue from Geom
	84
	85
	86
	87
	88	is
	89
	90
	91
	92
	93	Create (C : Curve from Geom; Offset : Real; V : Dir)
	94	returns mutable OffsetCurve
	95	---Purpose :
	96	-- C is the basis curve, Offset is the distance between <me> and
	97	-- the basis curve at any point. V defines the fixed reference
	98	-- direction (offset direction). If P is a point on the basis
	99	-- curve and T the first derivative with non zero length
	100	-- at this point, the corresponding point on the offset curve is
	101	-- in the direction of the vector-product N = V ^ T where
	102	-- N is a unitary vector.
	103	-- Warnings :
	104	-- In this package the entities are not shared. The OffsetCurve is
	105	-- built with a copy of the curve C. So when C is modified the
	106	-- OffsetCurve is not modified
107	raises ConstructionError;
108	---Purpose :
109	-- Raised if the basis curve C is not at least C1.
110	-- Warnings :
111	-- No check is done to know if \|\|V^T\|\| != 0.0 at any point.
112
113
114
115	Reverse (me : mutable);
116	---Purpose : Changes the orientation of this offset curve.
117	-- As a result:
118	-- - the basis curve is reversed,
119	-- - the start point of the initial curve becomes the
120	-- end point of the reversed curve,
121	-- - the end point of the initial curve becomes the
122	-- start point of the reversed curve, and
123	-- - the first and last parameters are recomputed.
124
125
126	ReversedParameter(me; U : Real) returns Real;
127	---Purpose: Computes the parameter on the reversed curve for
128	-- the point of parameter U on this offset curve.
129
130
131	SetBasisCurve (me : mutable; C : Curve from Geom)
132	raises ConstructionError;
133	---Purpose : Changes this offset curve by assigning C as the basis curve from which it is built.
134	-- Exceptions
135	-- Standard_ConstructionError if the curve C is not at least "C1" continuous.
136
137
138	SetDirection (me : mutable; V : Dir);
139	---Purpose : Changes this offset curve by assigning V as the
140	-- reference vector used to compute the offset direction.
141
142	SetOffsetValue (me : mutable; D : Real);
143	---Purpose : Changes this offset curve by assigning D as the offset value.
144
145
146	BasisCurve (me) returns Curve from Geom;
147	---Purpose : Returns the basis curve of this offset curve.
148	-- Note: The basis curve can be an offset curve.
149
150
151	Continuity (me) returns Shape from GeomAbs;
152	---Purpose : Returns the global continuity of this offset curve as a
153	-- value of the GeomAbs_Shape enumeration.
154	-- The degree of continuity of this offset curve is equal
155	-- to the degree of continuity of the basis curve minus 1.
156	-- Continuity of the Offset curve :
157	-- C0 : only geometric continuity,
158	-- C1 : continuity of the first derivative all along the Curve,
159	-- C2 : continuity of the second derivative all along the Curve,
160	-- C3 : continuity of the third derivative all along the Curve,
161	-- G1 : tangency continuity all along the Curve,
162	-- G2 : curvature continuity all along the Curve,
163	-- CN : the order of continuity is infinite.
164	-- Warnings :
165	-- Returns the continuity of the basis curve - 1.
166	-- The offset curve must have a unique offset direction defined
167	-- at any point.
168
169
170	Direction (me) returns Dir;
171	---Purpose : Returns the reference vector of this offset curve.
172	---C++: return const&
173
174	---Purpose : Value and derivatives
175	-- Warnings :
176	-- The exception UndefinedValue or UndefinedDerivative is
177	-- raised if it is not possible to compute a unique offset
178	-- direction.
179	-- If T is the first derivative with not null length and
180	-- V the offset direction the relation \|\|T(U) ^ V\|\| != 0
181	-- must be satisfied to evaluate the offset curve.
182	-- No check is done at the creation time and we suppose
183	-- in this package that the offset curve is well defined.
184
185
186	D0(me; U : Real; P : out Pnt);
187	---Purpose: Warning! this should not be called
188	-- if the basis curve is not at least C1. Nevertheless
189	-- if used on portion where the curve is C1, it is OK
190
191
192	D1 (me; U : Real; P : out Pnt; V1 : out Vec)
193	raises UndefinedDerivative;
194	---Purpose: Warning! this should not be called
195	-- if the continuity of the basis curve is not C2.
196	-- Nevertheless, it's OK to use it on portion
197	-- where the curve is C2
198
199
200	D2 (me; U : Real; P : out Pnt; V1, V2 : out Vec)
201	raises UndefinedDerivative;
202	---Purpose: Warning! this should not be called
203	-- if the continuity of the basis curve is not C3.
204	-- Nevertheless, it's OK to use it on portion
205	-- where the curve is C3
206
207
208
209	D3 (me; U : Real; P : out Pnt; V1, V2, V3 : out Vec)
210	raises UndefinedDerivative;
211	---Warning:
212	-- this should not be called
213	-- if the continuity of the basis curve is not C4.
214	-- Nevertheless, it's OK to use it on portion
215	-- where the curve is C4
216
217
218
219
220	DN (me; U : Real; N : Integer) returns Vec
221	---Purpose :
222	-- The returned vector gives the value of the derivative
223	-- for the order of derivation N.
224	--Warning!
225	-- this should not be called
226	-- if the continuity of the basis curve is not CN+1.
227	-- Nevertheless, it's OK to use it on portion
228	-- where the curve is CN+1
229
230	raises UndefinedDerivative,
231
232
233
234
235	---Purpose :
236	-- The following functions compute the value and derivatives
237	-- on the offset curve and returns the derivatives on the
238	-- basis curve too.
239	-- The computation of the value and derivatives on the basis
240	-- curve are used to evaluate the offset curve
241	--
242	-- Warning:
243	-- The exception UndefinedValue or UndefinedDerivative is
244	-- raised if it is not possible to compute a unique offset
245	-- direction.
246
247	RangeError;
248	---Purpose : Raised if N < 1.
249	--
250
251	Value (me; U : Real; P, Pbasis : out Pnt; V1basis : out Vec)
252	raises UndefinedValue;
253
254	---Purpose: Warning! this should not be called
255	-- if the basis curve is not at least C1. Nevertheless
256	-- if used on portion where the curve is C1, it is OK
257
258	D0 (me; U : Real; P, Pbasis : out Pnt; V1basis : out Vec)
259	raises UndefinedValue;
260	---Purpose: Warning! this should not be called
261	-- if the continuity of the basis curve is not C1.
262	-- Nevertheless, it's OK to use it on portion
263	-- where the curve is C1
264
265
266
267	D1 (me; U : Real; P, Pbasis : out Pnt; V1, V1basis, V2basis : out Vec)
268	raises UndefinedDerivative;
269	---Purpose: Warning! this should not be called
270	-- if the continuity of the basis curve is not C1.
271	-- Nevertheless, it's OK to use it on portion
272	-- where the curve is C1
273
274	D2 (me; U : Real; P, Pbasis : out Pnt; V1, V2, V1basis, V2basis,
275	V3basis : out Vec)
276	raises UndefinedDerivative;
277
278	---Purpose: Warning! this should not be called
279	-- if the continuity of the basis curve is not C3.
280	-- Nevertheless, it's OK to use it on portion
281	-- where the curve is C3
282	FirstParameter (me) returns Real;
283
284	LastParameter (me) returns Real;
285
286	--- Purpose: Returns the value of the first or last parameter of this
287	-- offset curve. The first parameter corresponds to the
288	-- start point of the curve. The last parameter
289	-- corresponds to the end point.
290	-- Note: the first and last parameters of this offset curve
291	-- are also the ones of its basis curve.
292
293	Offset (me) returns Real;
294	---Purpose: Returns the offset value of this offset curve.
295
296	IsClosed (me) returns Boolean;
297	---Purpose : Returns True if the distance between the start point
298	-- and the end point of the curve is lower or equal to
299	-- Resolution from package gp.
300
301
302	IsCN (me; N : Integer) returns Boolean
303	---Purpose : Returns true if the degree of continuity of the basis
304	-- curve of this offset curve is at least N + 1.
305	-- This method answer True if the continuity of the basis curve
306	-- is N + 1. We suppose in this class that a normal direction
307	-- to the basis curve (used to compute the offset curve) is
308	-- defined at any point on the basis curve.
309	raises RangeError;
310	---Purpose : Raised if N < 0.
311
312
313	IsPeriodic (me) returns Boolean;
314	---Purpose : Returns true if this offset curve is periodic, i.e. if the
315	-- basis curve of this offset curve is periodic.
316
317
318	Period (me) returns Real from Standard
319	---Purpose: Returns the period of this offset curve, i.e. the period
320	-- of the basis curve of this offset curve.
321	-- Exceptions
322	-- Standard_NoSuchObject if the basis curve is not periodic.
323	raises
324	NoSuchObject from Standard
325	is redefined;
326
327
328	Transform (me : mutable; T : Trsf);
329	--- Purpose: Applies the transformation T to this offset curve.
330	-- Note: the basis curve is also modified.
331
332	TransformedParameter(me; U : Real; T : Trsf from gp) returns Real
333	---Purpose: Returns the parameter on the transformed curve for
334	-- the transform of the point of parameter U on <me>.
335	-- me->Transformed(T)->Value(me->TransformedParameter(U,T))
336	-- is the same point as
337	-- me->Value(U).Transformed(T)
338	-- This methods calls the basis curve method.
339	is redefined;
340
341	ParametricTransformation(me; T : Trsf from gp) returns Real
342	---Purpose: Returns a coefficient to compute the parameter on
343	-- the transformed curve for the transform of the
344	-- point on <me>.
345	--
346	-- Transformed(T)->Value(U * ParametricTransformation(T))
347	-- is the same point as
348	-- Value(U).Transformed(T)
349	-- This methods calls the basis curve method.
350	is redefined;
351
352
353
354	Copy (me) returns mutable like me;
355	---Purpose: Creates a new object which is a copy of this offset curve.
356
357	fields
358
359	basisCurve : Curve from Geom;
360	direction : Dir;
361	offsetValue : Real;
362
363	end;