Mirror

The mirror plane is any flat face on the part — click the face the geometry should reflect across — or one of the base planes or a construction plane. If you pick a face, the mirror stays attached to it: move that face later and the reflection follows. A live preview shows the result before you commit.

The Result choice controls the output:

Merge into part. The reflected geometry joins the part.

• Point Mirror at a body and it reflects the whole body and fuses it back onto itself into one symmetric part — the headline use: model half a bracket, mirror it, and get the whole thing. Draw and detail one side, let Mirror complete the other.
• Point it at a feature (a boss, a pocket, a hole) and it re-applies that feature's own operation on the opposite side — the classic left-hand/right-hand pair. Because it re-reads the original on every rebuild, changing the source updates the mirrored side automatically, so the two stay a perfect reflection. The source has to be a feature that makes a solid, like an extrude, cut, or revolve — not a fillet or a move.

New body. The reflection becomes its own body in the same component — with its own editable history, so you can hide, move, change, or delete it independently of the original.

New component. The reflection becomes its own component — perfect for a left/right variant you want to evolve separately.

A merged mirror commits as an editable step in the history — reopen it to re-pick the plane or re-target it later. If the plane it uses is deleted, it tells you plainly instead of failing silently. New-body and new-component reflections commit as ordinary bodies and components (that's what makes them independent), so you edit each directly.

Mirror shares its plumbing with the Pattern tool — the same three result options, the same live, parametric rebuild.