- Wavefront OBJ (.obj)
- Collada Digital Asset Exchange (.dae)
- STEP (.stp)
- IGES (.igs)
For example consider the following statement:
#106 = IFCISHAPEPROFILEDEF(.AREA., $, #103, 302., 1008., 21., 40., 30.);This defines an I-beam profile cross-section with a 302mm width, 1008mm height, a thickness of 21mm for the web, 40mm for the flanges and a fillet radius of 30mm. The left-most image depicts how such a beam, with a single opening added, would be defined using triangles. Notice how the fillet radius where the web and the flanges meet is approximated using planar surfaces and the round opening is in fact an n-gon.
Where STEP and IGES are different is that these formats allow the exporter to specify the surfaces using a boundary representation that supports curved surfaces and faces with holes. Therefore, no geometrical fidelity is lost in the conversion process. This can be useful in many of the engineering applications that do not natively support importing IFC files, but do provide support for either STEP or IGES files. After all, even though STEP and IFC(-SPF) share the same notation format (ISO 10303-21), STEP has been around for longer and is used in a variety of domains, where IFC is used only for describing building data. An illustration of the same beam without the triangular tessellation is provided on the right.
Stay posted for the first Release Candidate of the new IfcOpenShell 0.4, to be made available soon, which includes this new utility!