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− | {{Autodesk_Revit}}
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− | = From Revit IFC 19.4.0.0 / 20.2.0.0 / 21.1.0.0 =
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− | {{warning|[https://github.com/Autodesk/revit-ifc/issues/290 An issue] with units mismatch has been raised by Jon Mirtschin}}
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− | Native input of global coordinates has been implemented in Revit IFC [https://github.com/Autodesk/revit-ifc/releases/tag/IFC_v19.4.0.0 19.4.0.0] / [https://github.com/Autodesk/revit-ifc/releases/tag/IFC_v20.2.0.0 20.2.0.0] / [https://github.com/Autodesk/revit-ifc/releases/tag/IFC_v21.1.0.0 21.1.0.0]. Although only for IFC4.
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− | == Set coordinates ==
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− | Specify your <code>Project Base Point</code> coordinates according to data given by your surveyor :
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− | [[File:RevitSetCoordinates.png]]
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− | Your <code>Project Base Point</code> should not move relatively to your building / elements. You might also want to apply coordinates to <code>Survey Point</code> to keep both at same location.
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− | Alternatively, you can unclip <code>Survey Point</code>, set coordinates in properties, re-clip it then move it to your <code>Project Base Point</code>. You still need to set angle to north in <code>Project Base Point</code>.
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− | You will also need to set the combined scale factor. This scale factor * surface distance = grid distance. Sometimes, surveyors will give you the opposite. The scale factor will be close to 1. Then, download the [https://raw.githubusercontent.com/Autodesk/revit-ifc/master/Install/Program%20Files%20to%20Install/IFC%20Shared%20Parameters-RevitIFCBuiltIn_ALL.txt Revit IFC shared parameters file], and add ProjectGlobalPositioning.Scale as a project parameter and make it apply to the Project Information category as an Instance parameter grouped under the "IFC Parameters" group. Insert the scale factor in the Project Information dialog when done.
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− | == Specify global positioning information during export ==
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− | # Modify your export setup
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− | # Select <code>Coordinate Base</code> -> <code>Project Base Point</code>
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− | # Input <code>EPSG Code</code>. It should be a valid EPSG number see [https://epsg.org EPSG website] or ask your surveyor.
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− | [[File:RevitGlobalPositioning.png]]
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− | == Result ==
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− | You should see an <code>IfcMapConversion</code> in your ifc file after export under <code>IfcProject.RepresentationContexts[0].HasCoordinateOperation[0]</code> :
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− | [[File:RevitIfcMapConversion.png]]
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− | = Before Revit IFC 19.4.0.0 / 20.2.0.0 / 21.1.0.0 =
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| Revit natively does not allow input of geolocated coordinates. Most users set the <code>N/S</code>, <code>E/W</code>, <code>Elev</code>, and <code>Angle to True North</code> parameters on the <code>Project Base Point</code> and <code>Survey Point</code> objects. Because this workaround is so common and many workflows depend on it, you may continue to apply this workaround without any modification. It is highly advised that the location in Revit of the <code>Project Base Point</code> and the <code>Survey Point</code> is the same. | | Revit natively does not allow input of geolocated coordinates. Most users set the <code>N/S</code>, <code>E/W</code>, <code>Elev</code>, and <code>Angle to True North</code> parameters on the <code>Project Base Point</code> and <code>Survey Point</code> objects. Because this workaround is so common and many workflows depend on it, you may continue to apply this workaround without any modification. It is highly advised that the location in Revit of the <code>Project Base Point</code> and the <code>Survey Point</code> is the same. |
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| <pre>$ ifcpatch -i input.ifc -r RemoveSiteRepresentation</pre> | | <pre>$ ifcpatch -i input.ifc -r RemoveSiteRepresentation</pre> |
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− | {{warning|There is currently an inconsistency in naming convention in buildingSMART international [https://buildingsmart-1xbd3ajdayi.netdna-ssl.com/wp-content/uploads/2020/02/User-Guide-for-Geo-referencing-in-IFC-v2.0.pdf User Guide for Geo-referencing in IFC]. See [https://forums.buildingsmart.org/t/geolocation-standards-in-ifc2x3-and-ifc4/2329/16 bsi forum thread] for more information.}}
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| == IFC4 Geolocation == | | == IFC4 Geolocation == |