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-- File: SurfaceTransition.cdl
-- Created: Thu Jan 30 12:10:44 1992
-- Author: Didier PIFFAULT
-- <dpf@sdsun1>
-- xpu:4/3/97 implementation
---Copyright: Matra Datavision 1992
class SurfaceTransition from TopTrans
---Purpose: This algorithm is used to compute the transition
-- of a 3D surface intersecting a topological surfacic
-- boundary on a 3D curve ( intersection curve ).
-- The boundary is described by a set of faces
-- each face is described by
-- - its support surface,
-- - an orientation defining its matter side.
-- The geometric elements are described locally at the
-- intersection point by a second order development.
-- A surface is described by the normal vector, the
-- principal directions and the principal curvatures.
-- A curve is described by the tangent, the normal
-- and the curvature.
-- The algorithm keeps track of the two faces elements
-- closest to the part of the curve "before" and "after"
-- the intersection, these two elements are updated
-- for each new face.
-- The position of the curve can be computed when at
-- least one surface element has been given, this
-- position is "In","Out" or "On" for the part of the
-- curve "Before" or "After" the intersection.
uses
Pnt from gp,
Dir from gp,
State from TopAbs,
Orientation from TopAbs,
Array2OfReal from TColStd,
Array2OfOrientation from TopTrans
is
Create returns SurfaceTransition from TopTrans;
---Purpose: Create an empty Surface Transition.
Reset ( me : in out;
Tgt : Dir from gp; -- curve tangent at this point
Norm : Dir from gp; -- surface normal at this point
MaxD, MinD : Dir from gp; -- surface principal directions at this point
MaxCurv, MinCurv : in Real ); -- curvatures on surface at this point
---Purpose: Initialize a Surface Transition with the local
-- description of the intersection curve and of the
-- reference surface.
-- PREQUESITORY : Norm oriented OUTSIDE "geometric matter"
Reset ( me : in out;
Tgt : Dir from gp;
Norm : Dir from gp );
---Purpose: Initialize a Surface Transition with the local
-- description of a straight line.
Compare(me : in out;
Tole : Real; -- Cosine tolerance
Norm : Dir from gp; -- surface normal oriented at this point
MaxD, MinD : Dir from gp; -- surface principal directions at this point
MaxCurv, MinCurv : in Real; -- curvatures on surface at this point
S : Orientation from TopAbs;
O : Orientation from TopAbs );
---Purpose: Add a face element to the boundary.
--
-- - S defines topological orientation for the face :
-- S FORWARD means: along the intersection curve on the
-- reference surface, transition states while crossing
-- the face are OUT,IN.
-- S REVERSED means states are IN,OUT.
-- S INTERNAL means states are IN,IN.
--
-- - O defines curve's position on face :
-- O FORWARD means the face is before the intersection
-- O REVERSED means the face is AFTER
-- O INTERNAL means the curve intersection is in the face.
-- PREQUESITORY : Norm oriented OUTSIDE "geometric matter"
Compare(me : in out;
Tole : Real;
Norm : Dir from gp;
S : Orientation from TopAbs;
O : Orientation from TopAbs);
---Purpose: Add a plane or a cylindric face to the boundary.
StateBefore(me) returns State from TopAbs;
---Purpose: Returns the state of the reference surface before
-- the interference, this is the position relative to
-- the surface of a point very close to the intersection
-- on the negative side of the tangent.
StateAfter(me) returns State from TopAbs;
---Purpose: Returns the state of the reference surface after
-- interference, this is the position relative to the
-- surface of a point very close to the intersection
-- on the positive side of the tangent.
--
-- Private :
--
UpdateReference(me : in out;
Tole : Real;
isInfRef : Boolean;
CosInf, CosSup : in out Real;
Tran : Orientation from TopAbs;
TranRef : in out Orientation from TopAbs) is private;
ComputeCos(me;
Tole : Real; -- cosinus tolerance
Norm : Dir from gp; -- face normal
O : Orientation from TopAbs; -- intersection position on face
isleft : out Boolean) returns Real is private;
GetBefore(myclass;
Tran : Orientation from TopAbs)
returns State from TopAbs;
GetAfter(myclass;
Tran : Orientation from TopAbs)
returns State from TopAbs;
fields
-- local reference input data :
myTgt : Dir from gp; -- intersection curve tangent
myNorm : Dir from gp; -- reference surface normal
beafter : Dir from gp; -- direction (Before, After) on reference surface.
myCurvRef : Real; -- for the reference surface
-- local data for boundary faces :
myAng : Array2OfReal from TColStd;
myCurv : Array2OfReal from TColStd;
myOri : Array2OfOrientation from TopTrans;
-- flag for touch case (eap Mar 25 2002)
myTouchFlag : Boolean from Standard;
end SurfaceTransition;
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