# \#xsd

**URL:** https://forums.buildingsmart.org/tag/xsd/63.md

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## [Missing attributes in XSD](https://forums.buildingsmart.org/t/missing-attributes-in-xsd/4025)

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**Author:** [@dansi](https://forums.buildingsmart.org/u/dansi)\
**Replies:** 0\
**Last updated:** [December 13, 2021, 12:30pm UTC](https://forums.buildingsmart.org/t/missing-attributes-in-xsd/4025 "2021-12-13T12:30:56Z")

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Hi, There seem to be missing attributes in ifcXML4.xsd. (The long version) All inverse relations are missing. Maybe I\`m missing a point here… Comparing IfcObjectDefinition in both exp and xsd definitions.

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## [Industry Foundation Classes are a Data Schema, not a file format](https://forums.buildingsmart.org/t/industry-foundation-classes-are-a-data-schema-not-a-file-format/1398)

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**Author:** [@jonm](https://forums.buildingsmart.org/u/jonm)\
**Replies:** 9\
**Last updated:** [November 11, 2019, 12:01pm UTC](https://forums.buildingsmart.org/t/industry-foundation-classes-are-a-data-schema-not-a-file-format/1398 "2019-11-11T12:01:47Z")

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Often a discussion topic seems to divert to the topic of IFC being STEP/Express and it’s evident that many involved would like to see more modern exchange formats. Here’s a discussion thread particularly on this topic. …