Thank you so much Dr. Lasso for your quick reply,
May i ask about the ruler Markup? It seems that it is only visible at the Sagittal plane of the MRI and also on the 3D section bit not for two other planes. I am aware of Markup line as a valid option but for the code i am working on i found measuring angle in real-time between rulers is easier and also better visualized in both the planes and 3D. Is there is a solution for this?
Also about the Measurements module Modules:Measurements-Documentation-3.6 - Slicer Wiki, it seems no longer supported for Slicer 4, is it the case?
Thank you again so much.