Extensible Storage vs Project Parameters – When should Extensible Storage be used?

[sHubamyadav016]

I am developing a Revit add-in that places and updates elements  based on project-wide values such as height and width.

Currently:

• The user can change project-wide values (e.g. panel height) via Project Parameters or a custom UI.

• My commands read these values and update geometry accordingly.

I understand that Extensible Storage stores data inside the  file and is not user-editable, while parameters are user-editable configuration.

My question is:

1. Is Extensible Storage intended mainly for state/metadata, such as:

   • Tracking which elements were created by my add-in

   • Storing relationships between generated elements

   • Versioning or ownership information

2. For user-editable, project-wide settings that affect the whole model (e.g. “project height ), is it correct to use Project Parameters instead of Extensible Storage?

3. Is it correct that Extensible Storage data is stored inside the RVT file, and the add-in DLL only defines the schema and access logic?

I want to make sure I am using Extensible Storage only where it is appropriate and not over-engineering my solution.

Any guidance or best-practice confirmation would be appreciated.
I there any best method for implementing project parameter like configuration file for whole  project or whole command how to do it 

[jeremy_tammik1]

both store data in the RVT and nowhere else

parameters are user editable and extensible storage is not

extensible storage is for everything you list in question 1 plus anything else you want

q2: for non-user-editable global settings, you can also use extensible storage in a custom datastorage element, cf.:

https://jeremytammik.github.io/tbc/a/1278_estorage_worksharing.htm

check the building coder topic group 5.23 extensible storage for many more tips and details.

cheers

jeremy