Snapping to grid and straight lines?

  • I'm been trying to do some perspective work and am using the line tool, but the lines are not quite straight and they don't line up on corners correctly so it looks a bit off.

    Is there some way to do these two things?

    1. When drawing a line is there some key combination I can hold with it that will keep the line "straight" so that it does not move from where I am at? The problem is partially when using my Wacom tablet as I lift away the pen it always moves slightly this causes the line to move out of position slightly.

    2. Is there a way when drawing lines, shapes, or anything else to force it to snap to grid? This would be very helpful for certain types of drawings.

  • Are you using the perspective rulers?