Knife Problems

Hello I’m new here and I’m just getting started with Blender, I watched some video tutorials.
the problem I’m having is this:

I have a question regarding bus or glitches ? on version 2.72
I want to cut a image from a plane
I pick mesh >image as a plane I resize center it
enter in Edit mode and choose knife.
there are 2 things happening

  1. I cut the image separate and move the image
    out of the plane select ‘origin to center of mass’ then Edit mode to
    extrude the image just to give it some volume
    the image only extrudes on one side the opposite side is hollow
    9 time out of 10 this happens with 1 success

  2. same procedure this time I press W to remove doubles (read it in old post here)
    I start cutting I go half way around the next point in the cut the pointer jumps
    to the top or the right side of the plane.

I have version 2.72 but I also had 2.82 I switched because most of the
videos I’ve been watching are in the older version
I can’t figure out why its glitching out like this.

  1. The only way an extrusion would leave the other side “hollow” is if you’re extruding face(s) that have other face(s) connected. Which is what it should do in that case. It’d be helpful if you could upload a .blend file demonstrating the issue so we could advise more to the point. If you’re new and can’t upload to this site directly yet, you can use an external hosting such as and post a link here. Please don’t use funky hostings with lots of advertisement.

  2. Knife snapping is normal. If it gets in the way, you should be able to temporarily disable it by holding shift.

Many Thanks Stan.

Hello Stan
I’ve reproduced the error successfully, I’ve attached a copy.
I also have 3 successes as well over 15 tries, so I can’t understand the randomness.
Could Bitdefender or other programs running in the background have such an effect ?

I appreciate your help in this matter.
Best Regards

issue.blend (417 KB)

I can’t tell for sure why it happened because it already happened :slight_smile: If you have it before extrusion that would help determine exactly the cause.