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-- File: ShapeAnalysis_Surface.cdl
-- Created: Wed Jun 3 12:01:25 1998
-- Author: data exchange team
-- <det@nnov.matra-dtv.fr>
---Copyright: Matra Datavision 1998
class Surface from ShapeAnalysis inherits TShared from MMgt
---Purpose: Complements standard tool Geom_Surface by providing additional
-- functionality for detection surface singularities, checking
-- spatial surface closure and computing projections of 3D points
-- onto a surface.
--
-- * The singularities
-- Each singularity stores the precision with which corresponding
-- surface iso-line is considered as degenerated.
-- The number of singularities is determined by specifying precision
-- and always not greater than 4.
--
-- * The spatial closure
-- The check for spatial closure is performed with given precision
-- (default value is Precision::Confusion).
-- If Geom_Surface says that the surface is closed, this class
-- also says this. Otherwise additional analysis is performed.
--
-- * The parameters of 3D point on the surface
-- The projection of the point is performed with given precision.
-- This class tries to find a solution taking into account possible
-- singularities.
-- Additional method for searching the solution from already built
-- one is also provided.
--
-- This tool is optimised: computes most information only once
uses
Pnt from gp,
Pnt2d from gp,
Box from Bnd,
Curve from Geom,
Surface from Geom,
Surface from GeomAdaptor,
HSurface from GeomAdaptor,
ExtPS from Extrema,
Array1OfPnt from TColgp,
Array1OfPnt2d from TColgp
is
Create (S : Surface from Geom) returns mutable Surface from ShapeAnalysis;
---Purpose: Creates an analyzer object on the basis of existing surface
Init (me : mutable; S: Surface from Geom);
---Purpose: Loads existing surface
Init (me : mutable; other: Surface from ShapeAnalysis);
---Purpose: Reads all the data from another Surface, without recomputing
SetDomain(me : mutable; U1, U2, V1, V2 : Real);
Surface (me) returns Surface from Geom;
---C++: return const &
---C++: inline
---Purpose: Returns a surface being analyzed
Adaptor3d (me : mutable) returns HSurface from GeomAdaptor;
---C++: return const &
---Purpose: Returns the Adaptor.
-- Creates it if not yet done.
TrueAdaptor3d (me) returns HSurface from GeomAdaptor;
---C++: return const &
---C++: inline
---Purpose: Returns the Adaptor (may be Null if method Adaptor() was not called)
Gap (me) returns Real;
---C++: inline
---Purpose: Returns 3D distance found by one of the following methods.
-- IsDegenerated, DegeneratedValues, ProjectDegenerated
-- (distance between 3D point and found or last (if not found)
-- singularity),
-- IsUClosed, IsVClosed (minimum value of precision to consider
-- the surface to be closed),
-- ValueOfUV (distance between 3D point and found solution).
Value (me : mutable; u,v : Real) returns Pnt from gp;
---C++: inline
---Purpose: Returns a 3D point specified by parameters in surface
-- parametrical space
Value (me : mutable; p2d : Pnt2d from gp) returns Pnt from gp;
---C++: inline
---Purpose: Returns a 3d point specified by a point in surface
-- parametrical space
ComputeSingularities (me: mutable) is private;
---Purpose: Computes singularities on the surface.
-- Computes the sizes of boundaries or singular ares of the
-- surface. Then each boundary or area is considered as
-- degenerated with precision not less than its size.
--
-- The singularities and corresponding precisions are the
-- following:
-- - ConicalSurface - one degenerated point (apex of the cone),
-- precision is 0.,
-- - ToroidalSurface - two degenerated points, precision is
-- Max (0, majorR-minorR),
-- - SphericalSurface - two degenerated points (poles),
-- precision is 0.
-- - Bounded, Surface Of Revolution, Offset - four degenerated
-- points, precisions are maximum distance between corners
-- and middle point on the boundary
--
---Remark: Considers only boundaries of the surface (i.e. does not detect
-- singularity if it is inside parametrical space)
HasSingularities (me: mutable; preci: Real) returns Boolean;
---Purpose: Returns True if the surface has singularities for the given
-- precision (i.e. if there are surface singularities with sizes
-- not greater than precision).
NbSingularities (me: mutable; preci: Real) returns Integer;
---Purpose: Returns the number of singularities for the given precision
-- (i.e. number of surface singularities with sizes not greater
-- than precision).
Singularity (me: mutable; num : Integer;
preci : out Real;
P3d : out Pnt from gp;
firstP2d, lastP2d: out Pnt2d from gp;
firstpar, lastpar: out Real;
uisodeg : out Boolean)
returns Boolean;
---Purpose: Returns the characteristics of the singularity specified by
-- its rank number <num>.
-- That means, that it is not neccessary for <num> to be in the
-- range [1, NbSingularities] but must be not greater than
-- possible (see ComputeSingularities).
-- The returned characteristics are:
-- preci: the smallest precision with which the iso-line is
-- considered as degenerated,
-- P3d: 3D point of singularity (middle point of the surface
-- iso-line),
-- firstP2d and lastP2d: first and last 2D points of the
-- iso-line in parametrical surface,
-- firstpar and lastpar: first and last parameters of the
-- iso-line in parametrical surface,
-- uisodeg: if the degenerated iso-line is U-iso (True) or
-- V-iso (False).
-- Returns False if <num> is out of range, else returns True.
---Remarks - all the singularities are sorted in ascending order by
-- precision
-- - firstP2d and lastP2d are such to define left-hand passing of
-- parametrical space
IsDegenerated (me: mutable; P3d : Pnt from gp;
preci: Real)
returns Boolean;
---Purpose: Returns True if there is at least one surface boundary which
-- is considered as degenerated with <preci> and distance
-- between P3d and corresponding singular point is less than
-- <preci>
DegeneratedValues (me: mutable; P3d : Pnt from gp;
preci : Real;
firstP2d, lastP2d: out Pnt2d from gp;
firstpar, lastpar: out Real;
forward : Boolean = Standard_True)
returns Boolean;
---Purpose: Returns True if there is at least one surface iso-line which
-- is considered as degenerated with <preci> and distance
-- between P3d and corresponding singular point is less than
-- <preci> (like IsDegenerated).
-- Returns characteristics of the first found boundary matching
-- those criteria.
---Remark : <forward> is not used
ProjectDegenerated (me: mutable; P3d : Pnt from gp;
preci : Real;
neighbour: Pnt2d from gp;
result : in out Pnt2d from gp)
returns Boolean;
---Purpose: Projects a point <P3d> on a singularity by computing
-- one of the coordinates of preliminary computed <result>.
--
-- Finds the iso-line which is considered as degenerated with
-- <preci> and
-- a. distance between P3d and corresponding singular point is
-- less than <preci> (like IsDegenerated) or
-- b. difference between already computed <result>'s coordinate
-- and iso-coordinate of the boundary is less than 2D
-- resolution (computed from <preci> by Geom_Adaptor).
-- Then sets not yet computed <result>'s coordinate taking it
-- from <neighbour> and returns True.
---Example: U-iso at Ufirst=0 is degenerated with 1e-03,
-- <neighbour> = (0, 0.5),
-- <result> = (1e-06, ?); (1e-06 - already computed, ? - not yet)
-- After, <result> will be (1e-06, 0.5): 0.5 is taken from <neighbour>
--
---Remark : This is only one method to compute the coordinate taking it
-- from neighbour point. Other methods are also possible (by
-- using tangent or C2, etc).
--
-- If the P3d is not on a singularity, no computation is done,
-- returns False and <result> remains unchanged
ProjectDegenerated (me: mutable; nbrPnt: Integer;
points: Array1OfPnt from TColgp;
pnt2d : in out Array1OfPnt2d from TColgp;
preci : Real;
direct: Boolean)
returns Boolean;
---Purpose: Checks points at the beginning (direct is True) or end
-- (direct is False) of array <points> to lie in singularity of
-- surface, and if yes, adjusts the indeterminate 2d coordinate
-- of these points by nearest point which is not in singularity.
-- Returns True if some points were adjusted.
IsDegenerated (me: mutable; p2d1, p2d2: Pnt2d from gp; tol, ratio: Real)
returns Boolean;
---Purpose: Returns True if straight pcurve going from point p2d1 to p2d2
-- is degenerate, i.e. lies in the singularity of the surface.
-- NOTE: it uses another method of detecting singularity than
-- used by ComputeSingularities() et al.!
-- For that, maximums of distances between points p2d1, p2d2
-- and 0.5*(p2d1+p2d2) and between corresponding 3d points are
-- computed.
-- The pcurve (p2d1, p2d2) is considered as degenerate if:
-- - max distance in 3d is less than <tol>
-- - max distance in 2d is at least <ratio> times greather than
-- the Resolution computed from max distance in 3d
-- (max3d < tol && max2d > ratio * Resolution(max3d))
-- NOTE: <ratio> should be >1 (e.g. 10)
Bounds (me; ufirst, ulast, vfirst, vlast: out Real);
---C++: inline
---Purpose: Returns the bounds of the surface
-- (from Bounds from Surface, but buffered)
ComputeBoundIsos(me : mutable);
---Purpose: Computes bound isos (protected against exceptions)
UIso (me: mutable; U: Real) returns Curve from Geom;
---Purpose: Returns a U-Iso. Null if not possible or failed
-- Remark : bound isos are buffered
VIso (me: mutable; V: Real) returns Curve from Geom;
---Purpose: Returns a V-Iso. Null if not possible or failed
-- Remark : bound isos are buffered
IsUClosed (me: mutable; preci: Real = -1) returns Boolean;
---Purpose: Tells if the Surface is spatially closed in U with given
-- precision. If <preci> < 0 then Precision::Confusion is used.
-- If Geom_Surface says that the surface is U-closed, this method
-- also says this. Otherwise additional analysis is performed,
-- comparing given precision with the following distances:
-- - periodic B-Splines are closed,
-- - polinomial B-Spline with boundary multiplicities degree+1
-- and Bezier - maximum distance between poles,
-- - rational B-Spline or one with boundary multiplicities not
-- degree+1 - maximum distance computed at knots and their
-- middles,
-- - surface of extrusion - distance between ends of basis
-- curve,
-- - other (RectangularTrimmed and Offset) - maximum distance
-- computed at 100 equi-distanted points.
IsVClosed (me: mutable; preci: Real = -1) returns Boolean;
---Purpose: Tells if the Surface is spatially closed in V with given
-- precision. If <preci> < 0 then Precision::Confusion is used.
-- If Geom_Surface says that the surface is V-closed, this method
-- also says this. Otherwise additional analysis is performed,
-- comparing given precision with the following distances:
-- - periodic B-Splines are closed,
-- - polinomial B-Spline with boundary multiplicities degree+1
-- and Bezier - maximum distance between poles,
-- - rational B-Spline or one with boundary multiplicities not
-- degree+1 - maximum distance computed at knots and their
-- middles,
-- - surface of revolution - distance between ends of basis
-- curve,
-- - other (RectangularTrimmed and Offset) - maximum distance
-- computed at 100 equi-distanted points.
ValueOfUV (me: mutable; P3D: Pnt from gp;
preci : Real)
returns Pnt2d from gp;
---Purpose: Computes the parameters in the surface parametrical space of
-- 3D point.
-- The result is parameters of the point projected onto the
-- surface.
-- This method enhances functionality provided by the standard
-- tool GeomAPI_ProjectPointOnSurface by treatment of cases when
-- the projected point is near to the surface boundaries and
-- when this standard tool fails.
NextValueOfUV (me: mutable; p2dPrev: Pnt2d from gp;
P3D : Pnt from gp;
preci : Real;
maxpreci:Real = -1.0)
returns Pnt2d from gp;
---Purpose: Projects a point P3D on the surface.
-- Does the same thing as ValueOfUV but tries to optimize
-- computations by taking into account previous point <p2dPrev>:
-- makes a step by UV and tries Newton algorithm.
-- If <maxpreci> >0. and distance between solution and
-- P3D is greater than <maxpreci>, that solution is considered
-- as bad, and ValueOfUV() is used.
-- If not succeded, calls ValueOfUV()
UVFromIso (me: mutable; P3D : Pnt from gp;
preci : Real;
U, V : in out Real)
returns Real;
---Purpose: Tries a refinement of an already computed couple (U,V) by
-- using projecting 3D point on iso-lines:
-- 1. boundaries of the surface,
-- 2. iso-lines passing through (U,V)
-- 3. iteratively received iso-lines passing through new U and
-- new V (number of iterations is limited by 5 in each
-- direction)
-- Returns the best resulting distance between P3D and Value(U,V)
-- in the case of success. Else, returns a very great value
UCloseVal (me) returns Real;
---C++: inline
---Purpose: Returns minimum value to consider the surface as U-closed
VCloseVal (me) returns Real;
---C++: inline
---Purpose: Returns minimum value to consider the surface as V-closed
GetBoxUF(me: mutable) returns Box from Bnd;
---C++: return const&
GetBoxUL(me: mutable) returns Box from Bnd;
---C++: return const&
GetBoxVF(me: mutable) returns Box from Bnd;
---C++: return const&
GetBoxVL(me: mutable) returns Box from Bnd;
---C++: return const&
ComputeBoxes(me: mutable) is private;
SurfaceNewton (me: mutable; p2dPrev: Pnt2d from gp;
P3D : Pnt from gp;
preci : Real;
sol :in out Pnt2d from gp)
returns Boolean is private;
SortSingularities (me: mutable) is private;
fields
mySurf : Surface from Geom is protected;
myAdSur : HSurface from GeomAdaptor is protected;
myExtPS : ExtPS from Extrema is protected; -- speed optimization
myExtSrf : Surface from GeomAdaptor is protected; -- for extrema
myExtOK : Boolean is protected; -- is theExtPS initialized?
myNbDeg : Integer is protected; -- < 0 means not yet computed
myPreci : Real [4] is protected;
myP3d : Pnt from gp [4] is protected;
myFirstP2d : Pnt2d from gp [4] is protected;
myLastP2d : Pnt2d from gp [4] is protected;
myFirstPar : Real [4] is protected;
myLastPar : Real [4] is protected;
myUIsoDeg : Boolean [4] is protected; -- True if U-iso is degenerated, False if V-iso
myIsos : Boolean is protected; -- are bound isos computed
myUF : Real is protected;
myUL : Real is protected;
myVF : Real is protected;
myVL : Real is protected;
myIsoUF : Curve from Geom is protected;
myIsoUL : Curve from Geom is protected;
myIsoVF : Curve from Geom is protected;
myIsoVL : Curve from Geom is protected;
myIsoBoxes : Boolean is protected; -- are boxes for bound isos computed
myBndUF : Box from Bnd is protected;
myBndUL : Box from Bnd is protected;
myBndVF : Box from Bnd is protected;
myBndVL : Box from Bnd is protected;
myGap : Real is protected;
myUDelt : Real is protected; -- what overparametrisation to have good ValueOfUV
myVDelt : Real is protected;
myUCloseVal: Real is protected; -- minimum value to consider the surface as U-closed
myVCloseVal: Real is protected; -- minimum value to consider the surface as V-closed
end Surface;
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