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buildingSMART / NextGen-IFC

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Should the next version of IFC adopt the latest version of STEP? #38

Open jwouellette opened 4 years ago

jwouellette commented 4 years ago

Description of the proposal: IFC2x3 and IFC4 still refer to an older version of STEP. Should IFC5 STEP serialization and schema concepts adopt the new 2016 version?

Describe how it contributes to the objectives set in https://github.com/buildingSMART/NextGen-IFC/wiki/Towards-a-technology-independent-IFC:

What do we win:

  1. Referencing
  2. UTF-8
  3. ... (need more elaboration)

What do we loose

Schema impact: Allow external referencing of other IFC files

Instance model impact: Ability to link multiple instance files

Backwards compatible: No

Automatic migration possible: No

Additional implications:

- Note that not all points need to be satisfied! Backwards compatibility and file size are not concerns.

Moult commented 4 years ago

From a comment during the meeting:

It is not necessary to adopt the STEP Part21Edition 3 to enable external references. The STEP AP214 External reference mechanism is applicable.

Moult commented 4 years ago

Refer to #9 too. Seems a duplicate.

TLiebich commented 4 years ago

I would propose to explicitly address this topic to the toolbox providers. Most implementers use a toolbox for the actual serialization. If the toolboxes adopt to ISO 10303-21:2016, then this becomes more a governance issue.

Other important and related question: it should be considered to make a clear cut here, i.e. all IFC5 instance files are only valid according to ISO 10303-21:2016 to avoid the chaos, if both versions are out at the same time. Certification (or other types of validation processes) have to ensure this.

berlotti commented 4 years ago

indeed duplicate. Decision made to move towards 2016 version of STEP ISO standard

TLiebich commented 4 years ago

one more point - but best to be opened as an additional issue. Do we also adopt the latest version of EXPRESS - ISO10303-11 in addition to the latest version of STEP physical file - ISO10303-21?