Docs / Retract Surface

Retract Surface

The opposite of Extend Surface: moves a surface body’s open edges inward along the surface, each edge by its own distance.

Where to find it

Select open edges or faces of a surface body, then Advanced Surface Tools tab › Retract Surface (Surfaces). OK trims the surface back.

Options

EdgesOpen edges of one surface body, each a line with its own distance (“Edge <1> 5 mm”). A picked face adds its open edges; several faces: the outline of the group.

DistanceSets the highlighted lines (Ctrl / Shift + click for several); with none highlighted, every line and new ones. Apply to all lines sets every line.

Round cornersWhere two retracted edges meet at a corner that opens up: round instead of sharp.

Show previewDraws the new edges as yellow lines, rebuilt after every change.

Step (mm)In Quality: how finely the edges are walked inward; smaller is more exact and slower.

How it works

Every point of an edge is walked inward along the surface itself, not in a plane: on a cylinder or a sphere the distance is measured on the surface. A walk that reaches another face continues on it, also over a sharp edge.

Edges you leave at 0 stay where they are. Closed faces work too: the rims of a full cylinder, a revolved part, a sphere cap.

Edit Feature opens rolled back to before the feature with its edges and distances in the list; other edges at OK move the feature, keeping its name and its place in the tree.

Good to know

Surface bodies only; a solid is refused with a message.
Only open edges: an edge between two faces of the surface (a cut inside it) is not supported yet, nor negative distances (extending).