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Rhino IFC Import
Importing IFC files into Rhino
ggImportIFC is a rhino command that will facilitate the import of an IFC data set from file into the active rhino document, converting the IFC elements with representation into the most appropriate rhino geometry equivalent.
IFC Import Options
The IFC file will have its own tolerance definition nominated. Often this value will be too constrained (ie 1e-5 metres) for successful rhino geometry creation. User can nominate to use file tolerance or nominate Rhino document tolerance (or user value). A lot of software will write out to extremely tight tolerance even though the nominated geometry might comply with a more relaxed tolerance. Import might also be much faster for relaxed tolerance.
This option relates to grid coordinates or georeferenced models. ****Rhino does not currently have a project base point. Not all programs embed remote co-ordinates into .ifc files but in the event it does, nominating to import to local coordinates will result in geometry local to project base point origin. Local Geometry will perform better for rendering and computations. Construction planes are generated to permit coordinate queries in grid coordinates.
IFC data set can nominate its own layer assignment to products. Rhino allows for a hierarchy layer system which can be handy for filtering different elements as a hierarchy of the model. The hierarchy for a building project will typically be site --> building --> storey --> possibly spaces. Import can then arrange different element types to allow easy viewing of different levels. If not it will use the layers if defined as IFC layer assignment.
Toggles creation of layers for spaces.
Global Ids can be prevented to be used for generated layers, which can improve situation where multiple IFC files are imported into rhino document and Global Ids are common to elements such as storeys or spaces.
Toggles whether presentation style nominates Rhino Material for purpose of rendering.
Representation maps in IFC are similar to a rhino block. Some IFC exports generate a representation map for many objects whether it's a single occurrence or has multiple instances. This import option can configure whether all representation maps generate a rhino block or a more selective approach is used.
Element Assemblies might make sense to be a single rhino block for some fabrication models, other users might prefer to have a single rhino object for each sub element, or a group created for the elements. Styling of sub products can be controlled by element assembly.
Create Rhino groups for elements that consist of multiple geometry representations such as multiple mesh or multiple breps/polysurfaces. Distinct multiple geometry objects might define a single element.
Generate user-text for properties of objects on the resultant rhino geometry object.
Generated user text keys can be prefixed with property set name or not (to identify grouping)
Some IFC exports are not schema compliant with elements orphaned from spatial structure containment. Enabling this option will ensure all elements are imported (searching for orphaned elements can be time consuming in large data sets).
Configure which objects you want to exclude/ignore when importing an ifc using a string such as "IfcSpace,IfcFurnishingElement,IfcFastener". Filtering to control inclusion is also possible.
Many built elements are best represented as an extrusion. Import can try to detect extrusions (including voided geometry) so resultant rhino model performs better. Import process will be slower to run detection.
Some IFC data sets nominate geometry with many ineffective boolean differences (or void cuts), which can trigger a large number of import warnings. Warnings can be disabled.
Creating faceted poly surfaces (or brep) in rhino is time consuming (particularly with high face count), so option is provided to generate a mesh as an alternative (if acceptable). Mesh generation is higher performant with smaller 3dm size. This allows you to set a threshold on which objects are generated as a polysurface or what is refered back to a mesh. A suggested value for this could be 300 faces. Set to zero for all poly surfaces.
Nominate an angle in degrees for unwelding mesh faces for improved rendering.
After import you will notice that Specific Rhino layers have been automatically created and element representation converted to rhino geometry assigned to those layers. The generation of these layers can be is dependent on the Import options provided.