Updated: Feb 21
We are going to do some crazy shit. Everyone knows the underground passages in KKND2: Krossfire. The Underground Passages are unique to the Desert Tileset. These allow infantry units to use routes that vehicles cannot use. There are two types of underground entrances and exits. On the left you see the pit and on the right the cave.
In this article I will explain how you can use them and what you have to pay attention to. I have rebuilt them in the Multiplayer Map "Ground to Air" so that vehicles can also use them. This is not possible everywhere and you have to pay a lot of attention that it also works but it gives your Maps or Missions another strategic option.
First of all, it is important to understand that the underground path can not be placed anywhere. You can place the entrances and exits where you want, only the connection must be there where otherwise no unit can be. As in my example video it is the cliff which is a Obstacle.
The underground passage is in the top layer and thus a unit driving along there would simply disappear. If you take a closer look at the underground passages in a mission you will find that they are always surrounded by some assets. Either they are cliffs or ditches or plants or stones. Something is always there. This also had the reason that no other unit was allowed to go there (except for flying units, which fly above the top layer).
Here you can see the top layer. This is the underground part, every unit that is there is covered by the top layer. To move some tiles in the top layer mark the desired tiles with the left mouse button and then press the right mouse button to open the context menu. Here you have to select "put up to top layer. Now we come to the attributes. Actually, the normal underground had the "Underground Attributes" which means that only infantry units are allowed to pass. That would be the easy way but since I want vehicles to be allowed to pass, I would have to come up with something else.
This is what the attributes look like, at the entrance and at the exit are "No Go" attributes. The underground passage ist outlined with "Impassable" attributes. The units move in this narrow corridor. I made the corridor 4 tiles wide so that oncoming traffic can pass.
What you cannot prevent is that flying units can land in the underground passages. This is because it is "normal ground" units must navigate around obstacles and therefore use the entrances/exits. Flying units don't need this, they just land there. You can only prevent this by filling the corridor with "Underground" attributes. But then only infantry units can pass. Feel free to try it out if you create a custom mission (optionally without planes) there are certainly many cool ideas that you can implement with it.
Thank you for your interest and I hope you enjoy the Multiplayer Map "Ground to Air" from the Series 9 campaign.