Bits of history: what happened to IFC 1x and 3x?

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I’ve long wondered: what happened to IFC 1x and 3x? When you look at the bSI schema specifications page, both are curiously absent. Other sources call out that IFC 1x had at least one major release - 1.5.1, in 1996. What became of those spec assets? I also can’t find a single reference to IFC3. Was it ever a release candidate?

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It’s just history, doesn’t worth bothering yourself too much with these questions.
The “x notation” was introduced (or invented) after the 2.0 release, as a substitute for the next version number, therefore the 1.x could not exist, while the 3.x version was swallowed by the 2x3, that’s why you can’t find any trace of it. :blush:

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I respectfully disagree. History does matter, even if it’s just a matter of curiosity.

Still eager if anyone is aware of old IFC 1.5 assets floating around (was there an EXPRESS schema?) or any primary sources on the version jumps.

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there is a history of IFC releases dating back to IFC 0.96 from Sept 1996 (including the express schemas). Actually IFC1.5.1 was issued in 1998 - since I got involved end of 1995, I still remember those humble beginnings. I once created a time line of all IFC releases (and the corresponding ISO standards). Need to find the time to retrieve it from my hard disks).

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Wow, very cool! Let’s all hope those hard disks still seek :slight_smile:

More seriously, it’d be great to save these assets for posterity. When you find the time, you have an eager audience.

Part of my curiosity centers around what the early IFC schema “felt” like. How many entities were there? Did it have objectified relations? What early choices had to be corrected or dropped in 2x? A schema definition would help here, but any primary source for “the early days” will give hints of design choices and tradeoffs.

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Agreed, very cool! I have found even when asking questions about IFC4 about the more esoteric portions of the spec (4D, 5D, project orders, resources), that looking back at IFC2X3 and seeing the evolution helps unearth some of the original intentions that may have been watered down over time (sometimes for the better, sometimes not).

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Hi Devon,

You can download IFC 1.51 Express schema from this link: https://ifcwebserver.org/schema/Ifc151_EXPRESS_LF.exp

If you are interested in comparing different IFC schema versions, you can use this link:
https://ifcwebserver.org/onfly_doc.rb

Included versions:

  • IFC2X_FINAL
  • IFC2X2_FINAL
  • IFC2X3_Final
  • IFC2X3G_ALPHA
  • IFC2X3_TC1
  • IFC_BRIDGE2X3
  • IFC2X3_TC1_PARAMETRIC
  • IFC2X3GE
  • IFC2X4_ALPHA
  • IFC2X4_BETA1
  • IFC2X4_BETA2
  • IFC2X4_BETA3
  • IFC2X4_RC1
  • IFC2X4_RC2
  • IFC2X4_RC3
  • IFC4RC4
  • IFC2X4_COBIE2012
  • IFC_BRIDGE2X3_EXT
  • IFC_ALIGNMENTEXTENSION
  • IFC2X3_CV_V2_0
  • IFC4
  • IFC4_ADD1
  • IFC4_ADD2
  • IFC4X1_FHWA
  • IFC20_LONGFORM
  • IFC4X3_ADD2
  • IFC4X3_DEV_0078979
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