2D geometry

Definition

Geometry type	Extrusion	Profile	Segments	Clipped	Slanted
2D Geometry

The IFC R2.0 model does not have separate geometry objects for 2D geometry. Instead the 2D geometry can be done using the same objects as in the the profile definitions.

• Polyline (straight segments only)
• Composite curve (straight and curved segments)
• Circle
• Ellipse

The 2D geometry is usually a symbolic representation (furniture, equipment, fixtures etc.) rather than a geometric projection of the 3D geometry.

There can be as many of these as needed in the Items collection of the IfcShapeRepresentation object. The collection is a set, which means that the items don't have any specific order. Z-ordering can be made by giving the Z-coordinates of each item a small offset. The polylines and composite curves can be open or closed as needed. Line styles and fills could be defined using PropertySets, but this system has not been defined yet.

Used by views

• Arch. design >> Quantities take off
• CAD / visualization

Data structure

Composite curve [1,2,3,5]
Circle [1,3,5]
Ellipse [1,3,5]
Polyline [all]

Uses concepts

Circle [1,3,5]
Composite curve [1,2,3,5]
Ellipse [1,3,5]
Polyline [all]

Used by concepts

Cabinet
Counter or shelf
Electrical appliance
Electrical fixture
Flow controller
Flow equipment
Flow fitting
Flow segment
Flow terminal
Furniture
Plumbing fixture

Copyright © 2000-2002 BLIS-Project [BLIS, Registered Organization]
Author: Jiri Hietanen (jiri@blis-project.org)
All rights reserved.