Can't find the proper lines on a flange to center a circular extrusion

[Anonymous]

Hi, i'm trying to create a circular extrusion on a face of a flange but i can't center the lines properly so that i can align the center of the flange with the center of the extrusion. The file i'm working on is a revit family obtained by importing the geometry from AutoCAD 3D, in the attachments you can find the screenshot of the situation i'm facing hence the circular extrusion not in the center of the flange. then i attached the .rfa and 3d dwg. file.

Thanks if someone comes into my help

[L.Maas · Accepted solution]

First create some reference planes. From a left or right view you can snap to the center of the pipe and drw a refernce plane. The same you can do from the plan view.

Than you have crossing reference planes at the center of the pipe/flange and you can add your extrusion