Struct Ifc4::IfcTransitionCode

Nested Relationships

This struct is a nested type of Struct Ifc4.

Struct Documentation

struct Ifc4::IfcTransitionCode

Public Types

enum Value

Definition from ISO/CD 10303-42:1992: This type conveys the continuity properties of a composite curve or surface. The continuity referred to is geometric, not parametric continuity. For example, in ContSameGradient the tangent vectors of successive segments will have the same direction, but may have different magnitude.

NOTE Corresponding ISO 10303 type: transition_code, please refer to ISO/IS 10303-42:1994, p. 14 for the final definition of the formal standard.

HISTORY New Type in IFC Release 1.0

Figure 273 (quoted from ISO/CD 10303-42:1992, p.55) illustrates transition types.

Figure 273 — Transition code

ENUMERATION

DISCONTINUOUS: The segments do not join. This is permitted only at the boundary of the curve or surface to indicate that it is not closed. CONTINUOUS: The segments join but no condition on their tangents is implied. CONTSAMEGRADIENT: The segments join and their tangent vectors or tangent planes are parallel and have the same direction at the joint: equality of derivatives is not required. CONTSAMEGRADIENTSAMECURVATURE: For a curve, the segments join, their tangent vectors are parallel and in the same direction and their curvatures are equal at the joint: equality of derivatives is not required. For a surface this implies that the principle curvatures are the same and the principle directions are coincident along the common boundary.

Values:

enumerator IfcTransitionCode_DISCONTINUOUS
enumerator IfcTransitionCode_CONTINUOUS
enumerator IfcTransitionCode_CONTSAMEGRADIENT
enumerator IfcTransitionCode_CONTSAMEGRADIENTSAMECURVATURE

Public Static Functions

IFC_PARSE_API const char *ToString(Value v)
IFC_PARSE_API Value FromString(const std::string &s)