Unable to Mirror

[Anonymous]

I'm two weeks into using  Fusion 360 and I'm creating a hollow corbel. I would like to mirror the extrusion from the left side to the right. However I am unable to select my mirror plane. It will be cut from MDF sheets and assembled. See the attached file.

[wmhazzard · Accepted solution]

You need to construct an offset plane first, 3" from the YZ plane. 

[Anonymous]

WMHazzard,

Thank you very much. Works great!