How to mirror an object in 3D scale

mirror puts object to other side of center line, but if center line is not between original and mirrored object place how to get it to right place

2 Answers

measure the distance between and create a line or plane at the halfway point.

Mirroring objects is pretty easy, a simple tutorial below :)
(i showed this for a sketch, but it works the exact same way for mirrored parts aswell, in that case you usually just use planes)

Answered with a tutorial: https://grabcad.com/tutorials/how-to-mirror-an-object-in-3d-scale