Tag: IFCEXPORT

Revit IFC Exports – the IfcExportAs parameter vs the Exporter mapping and preferences

Luke Johnson

An interesting discussion has been brewing over on LinkedIn about IFC Export from Revit. In my personal experience, the most predictable results come from deleting the IfcExportAs parameter and using the IFC mapping files to force the export result. However, this may not be the best path for data longevity and roundtripping.

Here is one little excerpt from Wawan Solihin:
The use of IfcExportAs is more suited for mapping detailed subtype or predefined type of MEP components that are mostly defined by families and often they do not correspond 1-1 nicely with IFC definitions. So instead of getting a generic IfcBuildingElementProxy for a family type that does not have clear mapping to the IFC entity, one can use IfcExporAs to define the IFC type it is intended to be plus its subtype for example IfcSensorType.CO2SENSOR that will create IFC entity IfcDistributionControlElement with type IfcSensorType and predefinedtype=’CO2SESNSOR’ in IFC2x3 (or entity IfcSensor in IFC4). This is just one example. There are other entities in IFC that must have mandatory attribute set, e.g. IfcReinforcingMesh which has several mandatory attributes such as LongitudinalBarNominalDiameter. Unless those attributes are set and Revit IfcExporter knows where to get the relevant information, you will get invalid entity information in IFC.

Read the whole thread:
http://www.linkedin.com/groups/Revit-IFC-Exports-3690870%2ES%2E5891816567016034308

Heads up via @theoryshaw

Converting a SAT file to IFC for Import to Revit and Navisworks and Exploding to individual forms (better element hierarchy)

Luke Johnson

This can be done with AutoCAD MEP 2015, or Architecture, or similar verticals that have the IFCEXPORT command.

  1. Open AutoCAD MEP
  2. New DWG file
  3. IMPORT -> select SAT file
  4. IFCEXPORT
  5. Open IFC in Revit

The advantage of doing this over importing the SAT directly to a Generic Model family is that the IFC method will result in individual forms for each bit of the SAT file. If there are 1200 forms, you will get 1200 families in Revit. This, in turn, will export to Navisworks with this level of element hierarchy (instead of just one big imported SAT element).

This will also result in higher granularity of clashes when using the converted SAT via IFC method (more forms to clash against).

You probably know that you can attempt to explode a SAT in a Revit family, but I find that sometimes unsupported elements disappear using this method… so I like my way via AutoCAD a bit better at this stage.