As a disclaimer, I'm an absolute scrub who's "experience" in this field is limited to one janky-ass demi-wall, visits to a few small-scale walls, and a lot of time on Sketchup. It should go without saying that I have no idea what I'm doing and my idea of what would make a good retail wall is basically based on me going "Oh that seems like it would be cool" or "I like climbing on this" or, in some cases, "What the hell can I even fit in this space." In no case should I be taken for an expert, and needless to say none of this stuff is intended to be, like, up to safety code or anything.
That said: Here's The Rock Box!
The idea for this wall was to make a full-featured gym in a concrete cube measuring 7.5 x 5 meters, with a height of 4.5 meters (to the lowest part of the roof). Obviously the "correct" way to build a gym in this sort of tiny location would be to expand the building, but I skipped that option here. Maybe the place is surrounded on all sides by, I don't know, historically-significant McDonalds locations or something. I don't know. This sort of small storage building is fairly common around Hokkaido so working with one of them is vaguely feasible. I guess. Needless to say, a facility of this size is going to be bouldering-only!
This location is not going to be heavy on the amenities, but in order to include as much floorspace as possible I added a second floor above the wall. Upon entering, we see a door to the main climbing area and a staircase to the upper deck, where the check-in desk will be. Space under the stairs can hold shoes and other storage, although this will necessarily be limited; behind the stairs is the bathroom. I'd like to note for the record here that I did include a fully-modeled sink and toilet, but didn't want to include a screenshot of just that. Oh well.
Entering through the main door we come onto the climbing floor. The climbing space is laid out in a fat L-shape, which as it turns out is hard to depict in screens. Inside the door we have a bulge wall with a 90-degree corner. One side of this corner is a 30 degree overhang, while the other is a 20. Originally, these were steeper, but they hung out into the rest of the room too far. The top of this wall is at three meters, and unfortunately working in a top-out was unfeasible (the check-in desk sits atop this segment).
This bulge adjoins the side wall of the gym, a vertical wall just over 3.5 meters in height. Nothing fancy here.
The side wall. You can see the bulge from the previous shot to the right. The side wall adjoins the back wall, which starts with another 20-degree overhang up to a short roof and flat finishing section. Were this wall ever to be built, it's possible that this wouldn't work, as climbers struggling for to stick holds on the finish might potentially swing out and fall off, potentially hitting the bulge or climbers on the bulge. But that's the joy of Fantasy Gyms!
Finally, the back wall. The 20-degree wall on the right of this shot is the same one as in the last shot, adjoining the side wall. The 20 degree transitions to a short vertical section and then into a 50/30 overhang. The vertical segment on the side of the steep overhang can be used for arete and side-reach moves, but mat coverage on this side isn't deep enough to allow for straight up climbing here (the door isn't very far from this bit). On the back wall, a support girder for the building structure is covered in a short sheath of plywood. This probably isn't much good for climbing, but is better than having an exposed metal girder. I can see some really godawful sit starts using this segment, as well.
Hopefully the layout of the wall is easy enough to visualize based on these shots. Here's an overhead of the climbing area:
The purple stuff is padding. The entrance to the climbing area is to the lower left. The bulge is in the center, with the overhangs of the back wall visible up top. Hey, there's that toilet I mentioned. Looking at it from this angle, the vertical segment of the big overhang might be climbable - the padding extends out about two meters. In a gym this size, every bit counts.
Last, here's the top deck. Stairs from the entryway lead up to the reception desk, which is the only really important thing up here. The rest of the top deck is simply there for relaxing and waiting; a walkway takes a climber over to the top of the big overhang, which is just large enough for a bench or a few seats. The reason I included all this is that the climbing floor is really too small for anybody who isn't actively climbing; if you aren't on the wall, you're in the way. The top deck was meant to alleviate this. It's not an ideal solution, but in a box this size it's probably the best you could do.
And, well, that's The Rock Box. I hope you enjoyed this exercise in theoretical bouldering gyms! Join us next time on Fantasy Gyms when we stick gyms in places they shouldn't go!
(I don't have any updates on my actual wall because I am currently installing 150+ T-Nuts on the 40-degree segment. I have to get this done before anything else can proceed because the damn thing is taking up nearly my entire kitchen and I don't want to store it until I've got the nuts in. The process is as exciting as it sounds.)