Very nice. Love the use of color key. The disadvantage with color key is that you can't really view the map at all with effects off, but it is a great effect to do a lot of things quickly and easy to change later.

Those of you who are active blog readers may already have noticed since I did publish it a week ago, but part 4 of my XP development series is now out, and it focuses on interacting with some of the core functionality on the CC3+ side of things, namely being able to interact with macro variables and call CC3+ commands from an XP.

Sorry for taking so long for the 4th part. I love writing these, but they also take a lot of time to prepare.

Those lines reminds me of the TCP 3-way handshake.

They are meant to be stairs, right? Perhaps making them with some steps and not just lines?

I was also thinking, since this is a cross section, and that hole in the middle still have a backing somewhere, perhaps apply a faded out version of the hatching as a background (perhaps with a tunnel for the stairs?)

And filling the sides with hatching did look much better than just edging it.

Considering that this is a side view, I would probably try out filling the area with hatching. It just doesn't work the same to just have edge-hatching as it does on overhead maps.

Use Draw -> Hex or Square Overlay

Note that CC3+ doesn't allow automatic creation of grids with variable thickness. You could either make two grids, or, since it sounds like you won't have that many whole-inch squares, you could probably just change those lines manually. The grid is a grouped entity, but you can unlock groups by hitting the Locked button in the bottom right, and now you can just use :CC2MCHANGE: on the grid lines you need to make thicker.

Note that you normally make maps in CC3+ in real-world scale, not paper scale, so grids aren't normally specified in inches, but since this is a rather abstract map, then perhaps you should just treat one map unit as one inch in this case.