PTR Changelog 2018-08-20: tunnels

• @artch yep, was cached. Thanks.

• @wtfrank Yes, that could happen. The main problem is that a creep shouldn't be able to stand on a wall when there isn't a road on it. This would be a little inconsistency in the game.

• Source Keeper already do

• @saruss They stand on a keeper lair. I'm talking about blank walls. That wasn't clear... Sorry.

• Amazing change. Nice work!

• I assume these would function the same as roads where they can only be created in neutral / owned / claimed rooms?

• @indijosh covered in penultimate line of post!

Other usual rules apply: you can build roads in neutral rooms, but any construction in hostile owned rooms is prohibited.

• This post is deleted!

• Again, this was just optimizing for energy, not CPU.

I think you need to consider both. IMO every step you hauler takes costs between ~2 energy per tick in CPU costs. That is to say that if you give me 0.2 CPU/tick I think I can make 2 energy/tick out of it.

So lets take an example of a max size hauler with a round trip time of 160 ticks. Lets say my room has 8 of these serving my remote sites and all my current roads are on plains and I don't do any sharing.

Energy cost for haulers per tick: 8 * 50 * 48 / 1500 = 12.8/tick Energy cost for roads per tick: 80 * 8 * 0.002 = 1.28/tick CPU cost: 8 * 0.21 = 1.68 CPU/tick.

With one extra CPU you can usually get about 10 extra energy harvested. So therefore the total energy/tick of this room spent on remotes is:

Total energy: 12.8 + 1.28 + (1.68 * 10) = 30.88 "enegy"/tick.

For what I'm about to do the road maintainance is a pain, so I'm just going to throw it away. Lets call total energy a conservative 29.6 energy/tick then.

Lets now say that it is possible to cut the total journey time by 12.5% using tunnels. That's 10 tiles off every one-way trip. This would let me use 7 haulers instead of 8. What is the break even point? Ie. what is the most number of tunnels I would want to build.

Well first off I'm saving ~3.7 energy/tick by cutting down my haulers. This is my budget. If I take your math above and agree that tunnels cost 0.2 energy a tick, that means I could build 18 tunnels and still turn a (very small) profit. These 18 tunnels would reduce the number of plains roads by 80, or ~4.5 roads per tunnel. Your result neglecting CPU was 10.

I suspect the real number is somewhere between: my case was designed to hit the breakpoint of saving 1 hauler, your case neglects CPU altogther.

So my prediction is that with the current upkeep tunnels will be in the occasional remote room but far from all of them. Owned rooms and SK rooms may be more popular. I think it's fine as is.

• @artch What is behavior of attacking tunnels? I assume they can be destroyed similar to roads. Are creeps in a tunnel killed instantly if the tunnel is collapsed? I guess they could just end up stranded in the middle of the wall.

• @davaned I mentioned that before. They just get stranded as you said.

@duckymirror Nothing happens is intended behavior.

• Also, you can now build ramparts on walls as well in order to protect expensive tunnels.

Ok, also a side question: if ramparts can be built on walls, does that mean we can build them on room controllers too? And if so, will the rampart protect the controller from getting attacked?

• Ramparts don't protect against attackController. It seems like they should. Along these same lines it should be possible to rampart the extractor as well.

It should be a quick PR to fix those.

• Update:

• Reverted ability to construct ramparts on natural walls. Tunnels still have enough their own hits, but they are considered to be dangerous place without an option to be easily defended.

• Tunnels cost increased from 100x to 150x.