Select an object to display metadata

I was wondering if anybody knows of a tutorial that would show me how to select an object and display metadata. For example, select a duct and display its size on the screen

Thanks

 

I also research the method show metadata of model same You. But when analysis Source code of unity Reflect, i feel, it so complex. So i decide write new code to select a duck and display its size on screen. That metadata imported to Unity throught PiXYZ Plugin.