HelixGeom — OpenCascade.js

OCCT package HelixGeom: HelixGeom_BuilderApproxCurve, HelixGeom_BuilderHelix, HelixGeom_BuilderHelixCoil, HelixGeom_BuilderHelixGen, and 2 more bound classes.

HelixGeom_BuilderApproxCurve

Base class for helix curve approximation algorithms.
This abstract class provides common functionality for approximating parametric helix curves using B-spline curves. It manages:

Approximation tolerance and parameters
Continuity requirements (C0, C1, C2)
Maximum degree and number of segments
Error and warning status reporting
Result curve storage
Derived classes must implement the Perform() method to execute the specific approximation algorithm.

Instance methods(8)

SetApproxParameters(aCont: GeomAbs_Shape, aMaxDegree: number, aMaxSeg: number): void
Sets approximation parameters.
Parameters (3)
- aCont
- aMaxDegree
- aMaxSeg
SetTolerance(aTolerance: number): void
Sets approximation tolerance.
Parameters (1)
- aTolerance
Tolerance(): number
Gets approximation tolerance.
ToleranceReached(): number
Gets actual tolerance reached by approximation algorithm.
Curves(): NCollection_Sequence_handle_Geom_Curve
Gets sequence of BSpline curves representing helix coils.
ErrorStatus(): number
Returns error status of algorithm.
WarningStatus(): number
Returns warning status of algorithm.
Perform(): void
Performs calculations. Must be redefined.

HelixGeom_BuilderHelix

HelixGeom_BuilderHelixGenHelixGeom_BuilderApproxCurve

Upper level class for geometrical algorithm of building helix curves using arbitrary axis.

Constructors(1)

constructor(): HelixGeom_BuilderHelix
Empty constructor.

Instance methods(3)

SetPosition(aAx2: gp_Ax2): void
Sets coordinate axes for helix.
Parameters (1)
- aAx2
Position(): gp_Ax2
Gets coordinate axes for helix.
Perform(): void
Performs calculations.

HelixGeom_BuilderHelixCoil

HelixGeom_BuilderHelixGenHelixGeom_BuilderApproxCurve

Implementation of algorithm for building helix coil with axis OZ.

Constructors(1)

constructor(): HelixGeom_BuilderHelixCoil
Empty constructor.

Instance methods(1)

Perform(): void
Performs calculations.

HelixGeom_BuilderHelixGen

HelixGeom_BuilderApproxCurve

Base class for helix curve building algorithms with parameter management.
This class extends HelixGeom_BuilderApproxCurve by adding helix-specific geometric parameters:

Parameter range (T1, T2) - angular range in radians
Pitch - vertical distance per full turn (2*PI radians)
Start radius (RStart) - radius at parameter T1
Taper angle - angle for radius variation (0 = cylindrical)
Orientation - clockwise or counter-clockwise
Concrete implementations include:
HelixGeom_BuilderHelix: Single helix approximation
HelixGeom_BuilderHelixCoil: Multi-coil helix approximation

Instance methods(2)

SetCurveParameters(aT1: number, aT2: number, aPitch: number, aRStart: number, aTaperAngle: number, bIsClockwise: boolean): void
Sets parameters for building helix curves.
Parameters (6)
- aT1
- aT2
- aPitch
- aRStart
- aTaperAngle
- bIsClockwise
CurveParameters(aT1: number, aT2: number, aPitch: number, aRStart: number, aTaperAngle: number, bIsClockwise: boolean): { aT1: number; aT2: number; aPitch: number; aRStart: number; aTaperAngle: number; bIsClockwise: boolean }
Gets parameters for building helix curves.
Parameters (6)
- aT1
- aT2
- aPitch
- aRStart
- aTaperAngle
- bIsClockwise
Returns
A result object with fields:
- aT1: updated value from the call.
- aT2: updated value from the call.
- aPitch: updated value from the call.
- aRStart: updated value from the call.
- aTaperAngle: updated value from the call.
- bIsClockwise: updated value from the call.

HelixGeom_HelixCurve

Adaptor3d_CurveStandard_Transient

Adaptor class for calculation of helix curves with analytical expressions.
This class provides parametric representation of helix curves including:

Cylindrical helixes (constant radius)
Tapered helixes (variable radius with taper angle)
Both clockwise and counter-clockwise orientations
The helix is defined by parametric equations in cylindrical coordinates:
x(t) = r(t) * cos(t)
y(t) = r(t) * sin(t) [* direction factor]
z(t) = pitch * t / (2*PI) where r(t) = rStart + taper_factor * t

Constructors(1)

constructor(): HelixGeom_HelixCurve
implementation of analytical expressions

Static methods(2)

get_type_name(): string
get_type_descriptor(): Standard_Type

Instance methods(16)

DynamicType(): Standard_Type
Load(): void
Sets default values for parameters.
Load(aT1: number, aT2: number, aPitch: number, aRStart: number, aTaperAngle: number, aIsCW: boolean): void
Sets helix parameters.
Parameters (6)
- aT1
- aT2
- aPitch
- aRStart
- aTaperAngle
- aIsCW
FirstParameter(): number
Gets first parameter.
LastParameter(): number
Gets last parameter.
Continuity(): GeomAbs_Shape
Gets continuity.
NbIntervals(S: GeomAbs_Shape): number
Gets number of intervals.
Parameters (1)
- S
Intervals(T: NCollection_Array1_double, S: GeomAbs_Shape): void
Gets parametric intervals.
Parameters (2)
- T —
  Mutated in place; read the updated value from this argument after the call.
- S
Resolution(R3d: number): number
Gets parametric resolution.
Parameters (1)
- R3d
IsClosed(): boolean
Returns False.
IsPeriodic(): boolean
Returns False.
Period(): number
Returns 2*PI.
EvalD0(theU: number): gp_Pnt
Computes the point of parameter theU on the curve.
Parameters (1)
- theU
EvalD1(theU: number): Geom_Curve_ResD1
Computes the point and first derivative at parameter theU.
Parameters (1)
- theU
EvalD2(theU: number): Geom_Curve_ResD2
Computes the point and first two derivatives at parameter theU.
Parameters (1)
- theU
EvalDN(theU: number, theN: number): gp_Vec
Returns the derivative of order theN at parameter theU.
Parameters (2)
- theU
- theN

HelixGeom_Tools

Static utility class providing approximation algorithms for helix curves.
This class contains static methods for:

Converting analytical helix curves to B-spline approximations
Generic curve approximation with specified tolerances and continuity
High-quality approximation suitable for CAD/CAM applications
The approximation algorithms use advanced techniques to ensure:
Accurate representation within specified tolerances
Smooth continuity (C0, C1, C2) as required
Efficient B-spline parameterization
Robust handling of edge cases

Constructors(1)

constructor(): HelixGeom_Tools

Static methods(2)

ApprHelix(aT1: number, aT2: number, aPitch: number, aRStart: number, aTaperAngle: number, aIsCW: boolean, aTol: number, theMaxError: number): { returnValue: number; theBSpl: Geom_BSplineCurve; theMaxError: number; [Symbol.dispose](): void }
Approximates a parametric helix curve using B-spline representation.
Parameters (8)
- aT1 —
  [in] Start parameter (angular position in radians)
- aT2 —
  [in] End parameter (angular position in radians)
- aPitch —
  [in] Helix pitch (vertical distance per 2*PI radians)
- aRStart —
  [in] Starting radius at parameter aT1
- aTaperAngle —
  [in] Taper angle in radians (0 = cylindrical helix)
- aIsCW —
  [in] True for clockwise, false for counter-clockwise
- aTol —
  [in] Approximation tolerance
- theMaxError —
  [out] Maximum approximation error achieved
Returns
A result object with fields:
- returnValue: 0 on success, error code otherwise
- theBSpl: [out] Resulting B-spline curve, owned by the returned envelope.
- theMaxError: [out] Maximum approximation error achieved
  Dispose the returned envelope to release owned Handle fields.
ApprCurve3D(theHC: Adaptor3d_Curve, theTol: number, theCont: GeomAbs_Shape, theMaxSeg: number, theMaxDeg: number, theMaxError: number): { returnValue: number; theBSpl: Geom_BSplineCurve; theMaxError: number; [Symbol.dispose](): void }
Approximates a generic 3D curve using B-spline representation.
Parameters (6)
- theHC —
  [in] Handle to the curve adaptor to approximate
- theTol —
  [in] Approximation tolerance
- theCont —
  [in] Required continuity (C0, C1, C2)
- theMaxSeg —
  [in] Maximum number of curve segments
- theMaxDeg —
  [in] Maximum degree of B-spline curve
- theMaxError —
  [out] Maximum approximation error achieved
Returns
A result object with fields:
- returnValue: 0 on success, error code otherwise
- theBSpl: [out] Resulting B-spline curve, owned by the returned envelope.
- theMaxError: [out] Maximum approximation error achieved
  Dispose the returned envelope to release owned Handle fields.