Knife project No other selected objects have wire or boundary edges to use for projection

When I try to use knife project (Blender 2.93.4), I get the error, " No other selected objects have wire or boundary edges to use for projection). While trying to figure out how I could be doing it wrong I came across a post on Blenderdev that said this describes the error so that people would know what the issue is, but obviously, I don’t know what that phrase means. Can anyone point me in the right directions?

I made a new file, created a plane and a cylinder, in object mode I selected the plane (the knife), then shift selected the cylinder (the object to cut), tabbed in to edit mode and selected Mesh>Knife project, and get the error.


I got blender (2.93.0) to that point by tinkering around, and then to a point where blender would not do knife project without an error. Both times tab out and back into edit mode seemed to fix it.

I found this shortly after posting this question, but I guess I still don’t understand because I can’t get it to work. Good luck.

I had the same issue with knife project. Then I deleted all the faces of my knife object keeping only the vertices & edges, it worked pretty well as I wanted.

Dang, I just tried that on a new file. Made a plane, delete the face only, tried it on the default cube, same error. Oh well.

I was going to submit a bug report and came across this way, so I was just doing it wrong.

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