I would like to know if it is possible to use the inset function while keeping part of the shape intact.

Circled is the part I don't want insetted, and I tried to show a global idea of what's the result I want to get with this. This knife/sword edge is one use case I can think of, but that would also be useful when insetting at the border of a mirrored object, to inset the global shape instead of just the half you're modifying.


3 Answers 3


One simple way is to temporarily extrude the shape and inset part of extrusion which will create edges on the boundary. So instead of a plane:
enter image description here

You use the same form but extruded (or just extrude one edge where you need edges to touch the boundary)
enter image description here

Then select top faces plus one on the side and run Inset: enter image description here

Dissolve unnecessary edges on the side as required (or delete bottom vertices to get rid of extrusion), note that dissolving might create Ngons which are better to avoid.


If you want the result to be clean and precise and the shape isn't rectangular, then I can only offer an awkward way to do this:

Select the edge and create a new transform orientation. Make sure the orientation is selected in the header.

enter image description here

Select the face, make sure a vertex of the edge is the active vertex, switch the pivot point to 'Active' and scale the face by -1 around the right axis, mirroring it along the edge.

enter image description here

Select everything, remove doubles and inset.

enter image description here

Delete the unneeded verts.

enter image description here

I tried other solutions but the only time the inset stays on the edge is if the edge has the same angle on both sides. If that's not the case, either the new verts miss the edge and create a jagged outline or, if corrected by hand, the inset differs in thickness.

I promised to do another awkward way of doing this and here it is:

Duplicate the bottom edge, scale it up and separate it with P.


Set the pivot point to 'Active Object, select the righ bottom vert, then Shift-select the top vert and scale up.

you crossed the line

Do the same with the left half. Select everything, then inset. Valiantly ignore the mess down there.

you crossed the line again

Select everything and use Knife Project.

drawing the line

Delete the unused verts. Find a good home for the stray edge.


Good for creativity, bad for workflow ( :


There is a way you can do this with a bit of modeling work.

  • Start with Inset (I)

  • Delete the bottom edge or faces

Cut out un needed geometry

  • Take note of the bottom edge you want to reach.

Note Location

  • In my plane it is just the Y axis.

Move edge

  • Move the middle edge to be parrallel to the bottom


  • You can apply this process to a 3d mesh pretty easily.
  • $\begingroup$ Nice solution too ! I can see this working in all cases indeed since inset should keep the edges parallel to their original counterpart. Thanks a lot $\endgroup$ Feb 27, 2018 at 17:43

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