Can't use "Knife Project" I tried to use the "Knife project" tool in order to shape a soda can ring but, even though I selected both the object supposed to cut and the object "to be cut", it only results in the message "No other selected objects found to use for projection", nothing else. What is causing this? How can I fix it? Thanks in advance.
Your shape seems closed, it looks like it can't work this way, so just open it: