i can’t figure out how sketchup assigns front and back to the faces of a 2D shape.
intuitively i would expect that the face i see when drawing it should be the front, but alas, every now and then it decides the back should be facing me, the human, looking at the screen.
it usually seems to do this when interacting with other objects on the screen, like drawing a rectangle inside of a larger rectangle.
SketchUp has a special rule that when drawing upon the ground plane, that the face is orientated facing down in preparation for a subsequent Pull-Pull operation.
Other faces in 3D space are orientated depending upon which direction you draw the vertices. (Ie, clockwise or counter-clockwise.)