I have 3D sketch turned off in preferences, but for some reason, my sketch is behaving like a 3D sketch:
As you can see from the screenshoot, there is only one sketch highlighted, yet the geometries exist on different planes. When I try to edit the sketch, it allows me to edit on both planes, but if I perform and extrude, I can only select from one plane at a time.
I have never seen this behavior before. Perhaps I confused Fusion 360 after repeatedly redefining the sketch plane?
Sketches in Fusion 360 are always 3D. The 2D related settings change the behavior of some commands to limit the construction and edit of geometry in a sketch so that the sketch geometry remains in the X-Y plane of the sketch. Here's a simple example. I create a new sketch and draw a few lines. Now I can use the Move command to move one of the points anywhere, including out of the X-Y plane.
With this point out of the X-Y plane, you can try drawing additional sketch geometry. If the "3D Sketch" setting is off then as you move the mouse over the sketch points, you'll see that you can only reference points that lie on the X-Y plane and the point moved out is not available. However, if you enable the "3D Sketch" option, then you can use the point. So the settings just help to keep things on a 2D plane but it's still possible to move things in 3D and it's always possible for a sketch to contain 3D geometry.
Thanks everyone for your help, but as shown in the screenshot below, I never had 3D sketch enabled. I was thinking perhaps the move command may have also created a problem, but I couldn't replicate the problem.
