# Infra-Common Schema
**URL:** https://forums.buildingsmart.org/c/projects/infra-common-schema/56.md
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## [About the Infra-Common Schema category](https://forums.buildingsmart.org/t/about-the-infra-common-schema-category/1396)
**Author:** [@jwouellette](https://forums.buildingsmart.org/u/jwouellette)\
**Replies:** 0
This category provides the community an opportunity to give feedback to the Infrastructure Extensions (IFC4.3) development team on the resulting schema and associated products. Schema documentation links: https://techni…
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## [Extension of IFC data schema in the Hydropower Industry](https://forums.buildingsmart.org/t/extension-of-ifc-data-schema-in-the-hydropower-industry/5383)
**Author:** [@shihangzhang](https://forums.buildingsmart.org/u/shihangzhang)\
**Replies:** 3\
**Last updated:** [May 29, 2024, 4:59pm UTC](https://forums.buildingsmart.org/t/extension-of-ifc-data-schema-in-the-hydropower-industry/5383 "2024-05-29T16:59:30Z")
Hi everyone, I believe that the ongoing extension of IFC data schema into the infrastructure sector is a very valuable endeavor. In the hydropower and water conservancy industry, there are still some highly specialized…
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## [openings in IfcSpatialElement](https://forums.buildingsmart.org/t/openings-in-ifcspatialelement/4425)
**Author:** [@hannu.lahtela](https://forums.buildingsmart.org/u/hannu.lahtela)\
**Replies:** 4\
**Last updated:** [October 15, 2022, 1:29pm UTC](https://forums.buildingsmart.org/t/openings-in-ifcspatialelement/4425 "2022-10-15T13:29:51Z")
How to make voids to spatial elements like IfcBridgePart? IfcBridgePart is not inherided from IfcElement but IfcSpatialElement. The IfcRelVoidsElement schema definition says: ENTITY IfcRelVoidsElement SUBTYPE OF (Ifc…
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## [IFC 4x1 file containing alignment is not opening in Civil 3D](https://forums.buildingsmart.org/t/ifc-4x1-file-containing-alignment-is-not-opening-in-civil-3d/3830)
**Author:** [@Anis](https://forums.buildingsmart.org/u/Anis)\
**Replies:** 2\
**Last updated:** [February 14, 2022, 2:12pm UTC](https://forums.buildingsmart.org/t/ifc-4x1-file-containing-alignment-is-not-opening-in-civil-3d/3830 "2022-02-14T14:12:05Z")
Hi! I am working on a highway project in a software named ProVI v6.2. I exported an alignment from this project using the IFC 4x1 format file (.ifc file). Then I tried to import that IFC file into Civil 3D 2022. The imp…
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## [Testing of the Linear Placement topic in the IFC Rail Implementers Forum](https://forums.buildingsmart.org/t/testing-of-the-linear-placement-topic-in-the-ifc-rail-implementers-forum/2947)
**Author:** [@Evandro](https://forums.buildingsmart.org/u/Evandro)\
**Replies:** 0\
**Last updated:** [September 8, 2020, 10:24pm UTC](https://forums.buildingsmart.org/t/testing-of-the-linear-placement-topic-in-the-ifc-rail-implementers-forum/2947 "2020-09-08T22:24:59Z")
Dear @igor.sokolov, thanks for your remarks below (and apologies for the late reaction). Context: These are known issues. In the context of the IFC Rail Implmenters Forum (IFC Rail-IF), we are just about to start testin…
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## [IfcOffsetCurveByDistances documentaion incomplete](https://forums.buildingsmart.org/t/ifcoffsetcurvebydistances-documentaion-incomplete/2899)
**Author:** [@igor.sokolov](https://forums.buildingsmart.org/u/igor.sokolov)\
**Replies:** 0\
**Last updated:** [August 14, 2020, 3:50am UTC](https://forums.buildingsmart.org/t/ifcoffsetcurvebydistances-documentaion-incomplete/2899 "2020-08-14T03:50:57Z")
Documentation does not define how to perform offset
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## [IfcOrientationExpression](https://forums.buildingsmart.org/t/ifcorientationexpression/2879)
**Author:** [@igor.sokolov](https://forums.buildingsmart.org/u/igor.sokolov)\
**Replies:** 0\
**Last updated:** [July 30, 2020, 4:09pm UTC](https://forums.buildingsmart.org/t/ifcorientationexpression/2879 "2020-07-30T16:09:14Z")
What is coordinate system of the Lateral- and VerticalAxisDirection ? Why do not use IfcAxis2Placement3D? Also our experts say this way to specify orientation is not compatible with ISO 19148 on LinearReferencing
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## [IfcLinearPlacement.PlacementMeasuredAlong - the curves location is not clear](https://forums.buildingsmart.org/t/ifclinearplacement-placementmeasuredalong-the-curves-location-is-not-clear/2898)
**Author:** [@igor.sokolov](https://forums.buildingsmart.org/u/igor.sokolov)\
**Replies:** 0\
**Last updated:** [August 14, 2020, 3:32am UTC](https://forums.buildingsmart.org/t/ifclinearplacement-placementmeasuredalong-the-curves-location-is-not-clear/2898 "2020-08-14T03:32:01Z")
IfcLinearPlacement.PlacementMeasuredAlong references to curve, but what coordinate system is used for the curve? Should I search IfcProduct that has the curve in Representations and use ObjectPlacement to have answer? O…