I'm using Type Light 3.2 and am struggling to find a reasonable way to prevent overlapping shapes "cancel out" and leave white areas in glyphs. How can I avoid this without having the overlaps be omitted by having the contours move past each other? E.g. having a )( shape instead of an X shape.
One thing you need to consider when creating your font is path direction.
Paths are filled based on their direction, so you create counters by drawing a path in the opposite direction (PostScript and TrueType disagree on the direction).
Ideally you want to avoid path intersections like you are describing. Some font editors have a function to flatten these intersections either before or on export so that may not be an issue. To prevent the "cancelling out" you are seeing, all you need to do is correct the path direction.
I haven't used Type Light so I can't say with any certainty about the specifics of that program, but a quick search shows there should be a reverse command in the contour menu. Use that on whichever one of the paths is in the wrong direction.
According to this post:
"With the full version you can use remove overlap on the contour menu to fix this. There is no easy way to merge the contours using Type light"