How do I add a 3D border on all edges of a mesh?

Question

I would like to add a 3D border to all edges of a mesh, such that the border is a "cylinder" that wraps around the mesh. The effect would look something like this:

My object is very similar to the white-textured part of the above image, it is a fully 2D mesh. However, differently to this mesh, the object is entirely one face, so I just need this effect applied to all edges of the mesh, and there's no edges in the middle that could get in the way.

Answer 1

One simple way is to duplicate the object (press Shift D, then Esc), enter edit mode, select all and press X to delete Only faces, then add a skin modifier, set the size of the quad border with the "Mean radius" X and Y values of every vertex, then add a subsurf modifier to get the resolution and roundness you need.

Afetr applying all modifiers (always starting from the upper) you can rejoin the two meshes into one single object (Ctrl J).

Answer 2

A non-destructive solution, provided the object is only one face with no inside edge :

• Add a Wireframe modifier
• Check "Boundary"
• Uncheck "Replace original"
• Set Material Offset to 1

• In the materials tab, make sure the material for the inside is in the first slot and the material for the boundary is in the second slot.

• Add a bevel modifier

• Set segments to 5
• Set width to a big number and make sure "clamp Overlap" is checked

All the vertices should be coplanar else the bevel will become wonky.