When does ProjectInformation GUID regenerate ?

[lvirone]

Hello,

I want to make a system which identify Revit files. I thought about using the projetInformation GUID but it seems when you save-as the new projetInformation  has the same GUID than the previous one. Too, when I generate two files using the same Revit Template, the two files have the same projetInformation GUID.

Am I missing something ? Is there another GUID for the model I didn't see ?

Thank you

EDIT : What worked for me : Using "ExporterIFCUtils.CreateProjectLevelGUID(doc, IFCProjectLevelGUIDType.Project)" is a good way to identify models if they are created using templates. If models are created by save-as or copy-paste, you need to add something else to identify a model like the fileName or the fullPath.

[ctm_mka · Accepted solution]

I believe they don't. That's sort of the point of GUID, a static identifier between projects.

[TripleM-Dev.net · Accepted solution]

Hi @lvirone,

It won't, only elements WITHIN ONE model are unique.

Within one Revitsession each opened document will have a unique Hash value, maybe that's enough?

Depending on needs there are some ways; save the central document fullfilename in the model with a GUID, and on open check if it's fullpath is still identical, if not generate a new GUID that you update somewhere in the model.

But if the model is recreated in another location as a new central model, this would mean it will get a new GUID.

Etc...

- Michel

[lvirone]

Hello @TripleM-Dev.net @ctm_mka 

Thanks for your quick answers. Yes I believe it's the correct behavior of a GUID to not change. But that's means if I create multiple projects using the same template, then all the files will have the same ProjetLocation UniqueID.

Yes I think the fullPath + UniqueId will be something good.

Thanks

[jeremy_tammik]

Afaik, all the built-in project identifiers will be duplicated by copying the project file. If you want to avoid that, you will have to undertake something yourself to prevent it. The same question was discussed briefly here:

• https://thebuildingcoder.typepad.com/blog/2017/12/project-identifier-and-fuzzy-comparison.html

I implemented a named GUID storage for project identification that may be of use to help handle this:

• https://thebuildingcoder.typepad.com/blog/2016/04/named-guid-storage-for-project-identification.html

[lvirone]

Hi @jeremy_tammik,

Thank you. What do you think about using "ExporterIFCUtils.CreateProjectLevelGUID(doc, IFCProjectLevelGUIDType.Project);" to identify a project from another ?

https://www.revitapidocs.com/2024/4b93559d-3541-5740-11f1-87f202977be5.htm

I think this method provide a different way to generate GUID, because it didn't use the UniqueId of the ProjectInformation to generate it. It seems to be different than what you eplained here : https://thebuildingcoder.typepad.com/blog/2009/02/uniqueid-dwf-and-ifc-guid.html

Thanks

[jeremy_tammik]

That sounds useful. It may have been implemented for the exact same purpose that you have. I have not used it myself, so I look forward to hearing how you fare with it. Thank you!

[lvirone]

What works for me : Using "ExporterIFCUtils.CreateProjectLevelGUID(doc, IFCProjectLevelGUIDType.Project)" is a good way to identify models if they are created using templates. If models are created by save-as or copy-paste, you need to add something else to identify a model like the fileName or the fullPath.