Release Notes

Import Dialogue Expanded

The functionality of the dialogue used to configure the import of IFC models was expanded to include the count of the various valid entity types and to automatically de-select entity types whose count is zero. For instance, in Figure 1, we can see that the number of IfcWall objects to be imported is 19. Correspondingly, its checkbox is checked.

The addition of this functionality is important because it allows the user to knowledgably select or de-select elements given their counts. Specifically of interest is the ability to de-select elements with very large counts whose inclusion is not important.

Figure 1: Import Dialogue Illustrating Changes.

Increased Number of Valid Entity Types

The entity types available for import into Sketchup now include IfcBuilingElementProxy, IfcCurtainWall, IfcFurnishingElement, IfcPlate, and IfcMember.

The addition of these elements allows a more complete rendering of the IFC file to sketchup, including various room divisions (IfcCurtainWall) which were not available, as well as furniture such as chairs, desks, etc. (IfcFurnishingElement). This change represents a large step towards the ability to import all IFC entity types.

Rendering Clipped Geometries

A big change in this release is the addition of functionality for rendering entities whose geometries are described by an IfcBooleanClippingResult. This includes specifically IfcBooleanClippingResult entities whose second operand is either an IfcHalfSpaceSolid or IfcPolygonalBoundedHalfSpace. Figures 2-5 illustrate the effects of clipping use in rendering IFC models to Sketchup:

Figure 2: A curved wall before clipping.

Figure 3: The same wall, after clipping.

Figure 4: A house before its highest walls were clipped.

Figure 5: The same house after clipping. Note that some of these walls had to be clipped twice.

Note: Because the algorithms used to perform the Boolean clipping require all input shapes to be convex, some assumptions were made about the use of IfcPolygonalBoundedHalfSpace objects. Instead of treating these as small subsections of a plane used to clip directly above the sections, they were treated as the full plane. Figure 6 illustrates the difference between ideal implementation and the current implementation. If this inconsistency poses a major problem, please use the previous version of the Ifc2Skp importer.

This figure illustrates the differences between correct rendering of an IfcBooleanClippingResult object whose second operand is an IfcPolygonalBoundedHalfSpace entity (middle) vs. incorrect rendering (right). On the left, we can see elements of an IfcBooleanClippingResult: an IfcExtrudedAreaSolid (black) and an IfcPolygonalBoundedHalfSpace (red). The middle figure shows the correct rendering Eonly the intersection is removed. On the right, we can see that everything above IfcPolygonalBoundedHalfSpace object's plane is removed.

Figure 6: Limitation of geometry clipping.