Grow/Shrink Selected: grow or shrink a selection by a distance

Grow/Shrink Selected grows (dilates) or shrinks (erodes) the selected triangles of a mesh, or the selected points of a point cloud, by a distance. Use it when the selection must change by the same amount everywhere, or to clean up a ragged selection. This guide also covers Grow/Shrink Selected Edges, the same tool for a selection of edges.

Distance or layers

Expand Selection and Shrink Selection change a selection by one layer of triangles per click, so the step depends on the size of the triangles: it is small where the mesh is fine and large where it is coarse. Grow/Shrink Selected changes the selection by a distance that you set, measured along the surface, so the result is the same on fine and coarse areas.

Grow or shrink a selection

1. Select triangles on a mesh or points on a point cloud.
2. Click Select › Grow/Shrink Selected.
3. Set Dilation distance and Erosion distance.
4. Click one of the four buttons. The panel stays open, so you can click again to grow or shrink further.

Parameter	What it does	Default
Dilation distance	How far Dilate grows the selection	1 mm
Erosion distance	How far Erode shrinks the selection	1 mm

Button	What it does
Dilate	Grows the selection by the dilation distance
Erode	Shrinks the selection by the erosion distance
Dilate & Erode	Grows the selection, then shrinks it. Gaps and holes in the selection that the growth closes stay closed, so use it to fill small gaps
Erode & Dilate	Shrinks the selection, then grows it. Small spots and thin spikes that the shrink removes do not come back, so use it to drop them

On a point cloud, use Dilate only: in MeshInspector 2.5.9, Erode, Dilate & Erode and Erode & Dilate remove the whole point selection instead of shrinking it.

Dilate & Erode and Erode & Dilate are available only when both distances are greater than zero. Each click is one undo step (Ctrl+Z, or Cmd+Z on macOS).

The button is unavailable when nothing is selected, and when all triangles or points are already selected. Select one mesh or one point cloud.

Grow/Shrink Selected Edges

Grow/Shrink Selected Edges grows or shrinks a selection of edges by a distance.

1. Select edges on the mesh, for example with the Edge Selector.
2. Open the drop-down arrow next to Grow/Shrink Selected and choose Grow/Shrink Selected Edges.
3. Set Distance: a positive value grows the selection, a negative value shrinks it.
4. Click Apply.

Parameter	What it does	Default
Distance	How far to grow (positive) or shrink (negative) the edge selection, measured along the surface	1 mm

With Distance set to 0, Apply does nothing. The button is unavailable when the mesh has no selected edges, and when all its edges are selected.