Offset Body and Offset Faces

Use Offset Body to grow or shrink a whole part, and Offset Faces to move only the faces you pick. Both fix the same problem: a part that is the right shape and the wrong size by a hair. Select a body for the first and one or more faces of one body for the second. Neither has a keyboard shortcut, so start them from the toolbar. Both take a signed distance: positive grows, negative shrinks.

Offset Body

The whole part grows or shrinks uniformly. Reach for it when a print comes out consistently 0.15 mm oversize, or when you need a copy of a part that has to be a press fit inside another.

There is no limit on the distance beyond being non-zero. Nothing stops you shrinking a part into nothing, and if you do, what you get back is a build failure rather than a range check:

Offset failed — the distance may be larger than a local feature of the part. Try a smaller distance.

Offset Faces

Only the faces you pick move, each along its own normal. This is the fit-tuning tool: the inside of a slot that is 0.2 mm too tight, one wall of a pocket, the top of a boss.

The body is worked out from the faces, so there is nothing to pick but faces, and they all have to belong to the same body.

Two things to know before relying on it:

• Its error messages come from Shell. Pick faces across two bodies and it complains that "all faces of one shell must belong to the same body". The rule is the same one, in borrowed wording. Re-pick inside a single body.
• It makes downstream references more fragile. Kapy cannot track a face through this operation, so a fillet or a sketch built on a face you offset may lose its target and need re-picking. Do your offsets before you build on them.

See also

• Cut and Push Face: moving one face with a distance you type
• Clearance Cut: giving a part room to fit
• Shell: the wall you may be tuning