I have a 3D object with planar faces that I'm trying to draw on the surface of. I used the Set Working Plane tool in Planar Face Mode. It highlights when I mouse over it, I click it, and the pink square shows that the working plane is now aligned with the planar face. Except, it's *almost* aligned with the face. It's actually slightly off. This is evident when I move my mouse around over the face, and I can watch edges of the preview "square" disappear under the face. When I try to draw lines on the face (after using the "Look At Working Plane") command, the lines start out above the face of the object, and then as I stretch the line across them, they disappear underneath. When I rotate the camera around, the lines are hanging out in mid-air, hovering above the object.
This planar face that I'm trying to draw on is not at any 90º angle to the ground - ones that are don't exhibit this issue. It's odd that it sets the working plane to be close, but not quite correctly. This...this has to be unintended, right? Or am I just Doing It Wrong?
[Edit] When said planar faces turn blue, they also (upon camera rotation) exhibit Z-fighting artifacts.
Resolved: Good grief, the face was not, despite my best efforts, actually planar. I didn't realize that was possible with how I constructed the geometry. Live and learn, I suppose.