mirror of
https://git.dev.opencascade.org/repos/occt.git
synced 2025-08-09 13:22:24 +03:00
ff8178ef85
Mostly duplicated comments were removed and missing ones were moved into dedicated class CDL files. Some more duplicated comments were removed from CDL files. Correction of merge
169 lines
7.8 KiB
Plaintext
169 lines
7.8 KiB
Plaintext
-- Created on: 1991-10-04
|
|
-- Copyright (c) 1991-1999 Matra Datavision
|
|
-- Copyright (c) 1999-2014 OPEN CASCADE SAS
|
|
--
|
|
-- This file is part of Open CASCADE Technology software library.
|
|
--
|
|
-- This library is free software; you can redistribute it and/or modify it under
|
|
-- the terms of the GNU Lesser General Public License version 2.1 as published
|
|
-- by the Free Software Foundation, with special exception defined in the file
|
|
-- OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
|
|
-- distribution for complete text of the license and disclaimer of any warranty.
|
|
--
|
|
-- Alternatively, this file may be used under the terms of Open CASCADE
|
|
-- commercial license or contractual agreement.
|
|
|
|
class BSplineSurfaceKnotSplitting from GeomConvert
|
|
|
|
--- Purpose : An algorithm to determine isoparametric curves along
|
|
-- which a BSpline surface should be split in order to
|
|
-- obtain patches of the same continuity. The continuity order is given at the
|
|
-- construction time. It is possible to compute the surface patches
|
|
-- corresponding to the splitting with the method of package
|
|
-- SplitBSplineSurface.
|
|
-- For a B-spline surface the discontinuities are localised at
|
|
-- the knot values. Between two knots values the B-spline is
|
|
-- infinitely continuously differentiable. For each parametric
|
|
-- direction at a knot of range index the continuity in this
|
|
-- direction is equal to : Degree - Mult (Index) where Degree
|
|
-- is the degree of the basis B-spline functions and Mult the
|
|
-- multiplicity of the knot of range Index in the given direction.
|
|
-- If for your computation you need to have B-spline surface with a
|
|
-- minima of continuity it can be interesting to know between which
|
|
-- knot values, a B-spline patch, has a continuity of given order.
|
|
-- This algorithm computes the indexes of the knots where you should
|
|
-- split the surface, to obtain patches with a constant continuity
|
|
-- given at the construction time. If you just want to compute the
|
|
-- local derivatives on the surface you don't need to create the
|
|
-- BSpline patches, you can use the functions LocalD1, LocalD2,
|
|
-- LocalD3, LocalDN of the class BSplineSurface from package Geom.
|
|
|
|
|
|
|
|
|
|
uses BSplineSurface from Geom,
|
|
Array1OfInteger from TColStd,
|
|
HArray1OfInteger from TColStd
|
|
|
|
raises DimensionError from Standard,
|
|
RangeError from Standard
|
|
|
|
is
|
|
|
|
|
|
Create (BasisSurface : BSplineSurface;
|
|
UContinuityRange, VContinuityRange : Integer)
|
|
returns BSplineSurfaceKnotSplitting;
|
|
--- Purpose : Determines the u- and v-isoparametric curves
|
|
-- along which the BSpline surface BasisSurface
|
|
-- should be split in order to obtain patches with a
|
|
-- degree of continuity equal to UContinuityRange in
|
|
-- the u parametric direction, and to
|
|
-- VContinuityRange in the v parametric direction.
|
|
-- These isoparametric curves are defined by
|
|
-- parameters, which are BasisSurface knot values in
|
|
-- the u or v parametric direction. They are identified
|
|
-- by indices in the BasisSurface knots table in the
|
|
-- corresponding parametric direction.
|
|
-- Use the available interrogation functions to access
|
|
-- computed values, followed by the global function
|
|
-- SplitBSplineSurface (provided by the package
|
|
-- GeomConvert) to split the surface.
|
|
-- Exceptions
|
|
-- Standard_RangeError if UContinuityRange or
|
|
-- VContinuityRange is less than zero.
|
|
|
|
NbUSplits (me) returns Integer is static;
|
|
--- Purpose : Returns the number of u-isoparametric curves
|
|
-- along which the analysed BSpline surface should be
|
|
-- split in order to obtain patches with the continuity
|
|
-- required by this framework.
|
|
-- The parameters which define these curves are knot
|
|
-- values in the corresponding parametric direction.
|
|
-- Note that the four curves which bound the surface are
|
|
-- counted among these splitting curves.
|
|
|
|
NbVSplits (me) returns Integer is static;
|
|
--- Purpose : Returns the number of v-isoparametric curves
|
|
-- along which the analysed BSpline surface should be
|
|
-- split in order to obtain patches with the continuity
|
|
-- required by this framework.
|
|
-- The parameters which define these curves are knot
|
|
-- values in the corresponding parametric direction.
|
|
-- Note that the four curves which bound the surface are
|
|
-- counted among these splitting curves.
|
|
|
|
|
|
Splitting (me; USplit, VSplit : in out Array1OfInteger)
|
|
--- Purpose: Loads the USplit and VSplit tables with the split
|
|
-- knots values computed in this framework. Each value
|
|
-- in these tables is an index in the knots table
|
|
-- corresponding to the u or v parametric direction of
|
|
-- the BSpline surface analysed by this algorithm.
|
|
-- The USplit and VSplit values are given in ascending
|
|
-- order and comprise the indices of the knots which
|
|
-- give the first and last isoparametric curves of the
|
|
-- surface in the corresponding parametric direction.
|
|
-- Use two consecutive values from the USplit table and
|
|
-- two consecutive values from the VSplit table as
|
|
-- arguments of the global function
|
|
-- SplitBSplineSurface (provided by the package
|
|
-- GeomConvert) to split the surface.
|
|
-- Exceptions
|
|
-- Standard_DimensionError if:
|
|
-- - the array USplit was not created with the following bounds:
|
|
-- - 1 , and
|
|
-- - the number of split knots in the u parametric
|
|
-- direction computed in this framework (as given
|
|
-- by the function NbUSplits); or
|
|
-- - the array VSplit was not created with the following bounds:
|
|
-- - 1 , and
|
|
-- - the number of split knots in the v parametric
|
|
-- direction computed in this framework (as given
|
|
-- by the function NbVSplits).
|
|
raises DimensionError
|
|
is static;
|
|
|
|
|
|
USplitValue (me; UIndex : Integer) returns Integer
|
|
--- Purpose : Returns the split knot of index UIndex
|
|
-- to the split knots table for the u parametric direction
|
|
-- computed in this framework. The returned value is
|
|
-- an index in the knots table relative to the u
|
|
-- parametric direction of the BSpline surface analysed by this algorithm.
|
|
-- Note: If UIndex is equal to 1, or to the number of split knots for the u
|
|
-- parametric direction computed in
|
|
-- this framework, the corresponding knot gives the
|
|
-- parameter of one of the bounding curves of the surface.
|
|
-- Exceptions
|
|
-- Standard_RangeError if UIndex is less than 1 or greater than the number
|
|
-- of split knots for the u parametric direction computed in this framework.
|
|
raises RangeError
|
|
is static;
|
|
|
|
|
|
VSplitValue (me; VIndex : Integer) returns Integer
|
|
--- Purpose : Returns the split knot of index VIndex
|
|
-- to the split knots table for the v parametric direction
|
|
-- computed in this framework. The returned value is
|
|
-- an index in the knots table relative to the v
|
|
-- parametric direction of the BSpline surface analysed by this algorithm.
|
|
-- Note: If UIndex is equal to 1, or to the number of split knots for the v
|
|
-- parametric direction computed in
|
|
-- this framework, the corresponding knot gives the
|
|
-- parameter of one of the bounding curves of the surface.
|
|
-- Exceptions
|
|
-- Standard_RangeError if VIndex is less than 1 or greater than the number
|
|
-- of split knots for the v parametric direction computed in this framework.
|
|
raises RangeError
|
|
is static;
|
|
|
|
|
|
|
|
fields
|
|
|
|
usplitIndexes : HArray1OfInteger;
|
|
vsplitIndexes : HArray1OfInteger;
|
|
|
|
end BSplineSurfaceKnotSplitting;
|