Shrink Selection removes one layer of triangles from the border of a triangle selection. Use it to pull a selection back from its edge, for example to cut off the spikes along a jagged border or to undo one step of Expand Selection. This guide also covers Shrink Selected Edges, the same step for a selection of edges.
Shrink a triangle selection by one layer
- Select triangles on the mesh.
- Click Select › Shrink Selection or press Ctrl+- (Cmd+- on macOS).
- Repeat to remove more layers.
The tool works at once, without a panel. Each click unselects every selected triangle that shares an edge with an unselected triangle, so thin spikes along the border disappear first. To undo a step, press Ctrl+Z (Cmd+Z on macOS).
Selected edges work as a fence: where the border of the selection runs along selected edges, it does not shrink. A layer is as wide as the triangles at the border. To shrink a selection by a distance in mm instead, use Erode in Grow/Shrink Selected. Shrink Selection is unavailable when the mesh has no selected triangles, and when all its triangles are selected.
Shrink Selected Edges
Shrink Selected Edges removes one layer of edges from the border of an edge selection. It is useful for a wide area of edges, for example one selected with the lasso of the Edge Selector.
- Select edges on the mesh.
- Open the drop-down arrow next to Shrink Selection and choose Shrink Selected Edges.
The tool works at once, without a panel. It takes the vertices of the selected edges, drops every vertex that has a neighbor outside this set and keeps the edges between the remaining vertices. On a contour that is only one edge wide, every vertex has such a neighbor, so one click clears the whole contour. The button is unavailable when the mesh has no selected edges. To add a layer of edges, use Expand Selected Edges.
