Rhino IFC Import
Importing IFC files into Rhino
Import
ggImportIFC
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.
Import Options
Import Tolerance
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.
Local Coordinates
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.
Hierarchy Layer Structure
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.
Layers for Spaces
Toggles creation of layers for spaces.
Save GlobalId on Layers
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.
Object Material from Presentation Style
Toggles whether presentation style nominates Rhino Material for purpose of rendering.
Representation Maps as Blocks
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
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.
Group objects
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 option
Generate user-text for properties of objects on the resultant rhino geometry object.
Prefix Property Set Name
Generated user text keys can be prefixed with property set name or not (to identify grouping)
Identify Orphaned Elements
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).
IFC Object Filter
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.
Correct and improve geometry
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.
Ignore Boolean Difference Failures
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.
Faceted Brep Options
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.
Mesh Unweld Angle
Nominate an angle in degrees for unwelding mesh faces for improved rendering.
On Import
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.
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