Definition from IAI: The IfcTShapeProfileDef defines a section profile that provides the defining parameters of a T-shaped section to be used by the swept area solid. Its parameters and orientation relative to the position coordinate system are according to the following illustration. The centre of the position coordinate system is in the profiles centre of the gravity bounding box.

The centre of gravity, if given, is located in x direction within the center of the bounding box, and in y-direction along the positive y axis, the offset value is given by the offset parameter CentreOfGravityInY.

HISTORY  New entity in Release IFC2x Edition 2.

IFC2x Edition 3 CHANGE  All profile origins are now in the center of the bounding box. The attribute CentreOfGravityInY has been made OPTIONAL. Upward compatibility for file based exchange is guaranteed.

Illustration:

Position The parameterized profile defines its own position coordinate system. The underlying coordinate system is defined by the swept area solid that uses the profile definition. It is the xy plane of: IfcSweptAreaSolid.Position by using offsets of the position location, the parameterized profile can be positioned centric (using x,y offsets = 0.), or at any position relative to the profile. Explicit coordinate offsets are used to define cardinal points (e.g. upper-left bound). Parameter The parameterized profile is defined by a set of parameter attributes, see attribute definition below.

Table: Parameters of T-shape profile definition