buildingSMART Forums

ISG Fall 2018 Meeting (#67) - Munich


13 & 14 September 2018
Munich, Germany

Meeting hosted by ALLPLAN Deutschland GmbH
Dinner hosted by OBERMEYER Planen + Beraten GmbH

Please register your attendence, as soon as possible, via Doodle:

Meeting Location:
Nemetschek Group
Konrad-Zuse-Platz 1
81829 Munich
Room: Brussels/Bordeaux
Lunch will be in our Company Restaurant

A block is reserved in the H2 Hotel ( ) which can be booked until August 14., Code Name “ISG”.

  • The Rate for 2 Days is 175 Euro (from 12. – 14. September).
  • Reservation can be canceled up to 4 Weeks before arrival without any Charge, otherwise 90% of the fee are charged.
  • Parking is 18 Euro/Day.


Cheaper Hotels in the City Center with better cancelling Conditions might be possible. ALLPLAN can also recommend the MotelOne, a quality low cost Hotel Chain ( ). There are several of them still available in September.

Connection to Nemetschek House from the City by Public Transportation is excellent, Subway Station (Line “U2”, Station “Messestadt West”) is 5 Minutes Walk from the Office.

Host Dinner (OBERMEYER):

  • Augustiner Bräustuben
    • Landsberger Straße 19, 80339 München
    • September 13th from 19:00-22:00 (basically open end)

Agenda (proposed/tentative – please propose other agenda items to Angel and Jeff prior to 01 SEPT 2018. Any attempt to add after that date will NOT be considered):

Thursday AM:

  • ISG business
    • IFC4 Certification updates – R. Steinmann
    • DTV 1.x refinement
    • Outstanding issues
      • Finalize ISG charter – Structure, mission, operations, etc.
      • Finalize IFC intent/use/scope documentation
      • Communications
  • bSI business
    • bSI Product Strategic Planning initiative update – G. Schleusner
    • bSI Room/Project/Summit updates
    • Utilizing new web technologies
  • End user presentations:
    • Presentation about the advancements in IFC/BIM research from TUM (Technical University Munich) – S. Markic

Thursday PM / Friday:

  • MSG business
    • IFC+ development – T. Liebich/M. Weise
  • Workshops (planned to be the majority of our time)
    • IFC5 – Proposals from ISG for changes, additions, enhancements
    • IFC open Toolkit – Where to Begin? Bootstrapping and moving forward
1 Like

Thanks, Motel One is a good choice.


I’ve made some updates to the Agenda. If there are any other agenda items to be considered, please post them here.


Proposal to agenda: Refine Precision (tolerance): Improve definition; Different geometry aspects coming from precision: points resolution, planarity, singular areas, angles and directions, NURBs; Expected b-cert checks(restrictions to IFC file)


Hi Igor,

Can the NURBS discussion be handled in the Certification calls?

Do you feel the precision issue affects IFC5 or is it urgent to tackle at this point for certification?


Can the NURBS discussion be handled in the Certification calls?
. ……… No (this is out of RV scope)

Do you feel the precision issue affects IFC5 or is it urgent to tackle at this point for certification?
. ………………… Yes …………………………………………. No


Hello Jeffrey. I would like to discuss 3 new topics during the meeting:

1/ How to setup internal test rounds to enhance interoperability between systems ? STEP and JT Implementor forums have regular test rounds and dedicated infrastructure for that. May be we could setup something light to test and enhance the IFC4 functionalities like tessellation, AdvancedBRep, Alignments.

2/ IFC files are monolithic. I have received from a customer a file which is 2.6Gb large … ! I think it is time to consider multi-files exchanges (IFC model defined in several files: one or several for the structure + one file for each ShapeRepresentation). This is available in STEP for a long time and was introduced to solve big data issues (exchange of a plane or a car).

3/ Instance/Reference: I have identified at least 35 ways to describe two identical products in IFC (2 windows with same geometry and same properties). ObjectTypes can be used but they can be used also for describing families. I suggest to work on a recommendation.

Best Regards.


We have discussed IFC file split some times and would be nice to move forward in this.
I agree the simplest way is to have one master file wit elements and all relations and allow geometry representation be an external resource.
As starting suggestion I would suggest entities like following:

ENTITY IfcExternalRepresentationItem
SUBTYPE OF (IfcGeometricRepresentationItem);
Location : IfcExternalReference;

ENTITY IfcExternalIfcRepresentationItem
SUBTYPE OF (IfcExternalRepresentationItem);
StepId : IfcInteger
(Where reffered item is subtype of IfcGeometricRepresentation item)

Some issues to solve are geometrical context (possibly master file should provide), points identity, BCF(?)


Hi, if we want to support split of files and use of external references from any instance of an IFC file, I would recommend to update to ISO 10303-21 ed. 3 - which has support for it (instead of creating an individual solution). Alternatively put more effort into supporting ifcXML (and using the built-in external reference mechanism of XML).


Sure, if this is supported at lower level it is a good choice.
Is there ed.3 in public free access?


Here is a new version of the Proposed Agenda.
bSI-ISG67_Agenda.pdf (69.0 KB)
Please review and be sure to be prepared for the discussions.


Meeting Notes and presentations have been posted to the ISG ShareFile.

Sheila should’ve added you to the folder if you were in the bSI-Intranet and active ISG list. If you need access, please let me know.


Hi jeff and ISG

what was the outcome of the Model Setup discussion?
Are there any actions for Tokyo?
I’m still awating a template /style guide for final documentation.
Does ISG have any recommendations on techical issues such as time dependency (AU is planning on adopting after 2020), capturing reference points, caturing accuracy issues??

As I’m scheduled to talk about MSI on the final plenary at Tokyo, any ISG feedback would be welcome.



I’m not registered on FilShare with my e-mail address.
Could you fix this?
E-mail address:

I need this MoM during the weekend for preparation for my meeting in Norway Monday - if possible


I thought I added you on Thursday. Let me look at it and try again.


Hi Jeff,
I also have no access to FilShare. Could you please register me also:
Thanks and Bye


Hello Jeffrey.
I don’t have access to the ISG ShareFile. I tried to connect with my bsi-intranet login and forums.buildingsmart login but both failed.
Can you register me too ?


Hi John,

We need to work a bit more on this after Tokyo. Due to some unexpected circumstances, we need to figure out how to get the IfcDoc Tool end to work for this project. Please be patient.

In Tokyo, we can talk about the other issues. I’m optimistic we can get the vendors to support by 2020 timeframe. Getting the mvdXML process working will help.