Definition from IAI: A container class that represents complex
element assemblies aggregated from several elements, such as discrete elements,
building elements, or other elements.
EXAMPLE: Steel construction assemblies, such
as trusses and different kinds of frames, can be represented by the
IfcElementAssembly entity. Other examples include slab fields aggregated
from a number of precast concrete slabs or reinforcement units made from
several reinforcement bars.
HISTORY: New Entity for Release
IFC2x Edition 2.
Geometry Use Definitions
The geometric representation of IfcElementAssembly is given by
the IfcProductDefinitionShape, allowing multiple geometric
representations.
Local Placement
The local placement for IfcElementAssembly is defined in its
supertype IfcProduct. It is defined by the IfcLocalPlacement,
which defines the local coordinate system that is referenced by all geometric
representations.
- The PlacementRelTo relationship of IfcLocalPlacement
shall point (if given) to the local placement of the same
IfcBuildingElement, which is used in the Decomposes inverse
attribute, i.e. the local placement is defined relative to the local placement
of the building element in which the assembly is contained.
- If the relative placement is not used, the absolute placement is
defined within the world coordinate system.
Geometric Representations
The geometry of an IfcElementAssembly is generally formed from
its components, in which case it does not need to have an explicit geometric
representation. In some cases it may be useful to also expose a simple explicit
representation as a bounding box representation of the complex composed shape
independently.
