As the name suggest it allows boats to pass under bridges, the system has some flaws, but is the best that is available. Gives a good start for a trigger setup, but doesn't explain the system.
This guide will show you how to make ships able to pass you bridges. Units can also pass them of course.. I'll do it with the Trireme (Greek arrow ship)
The difference of the method and other (like this one using telport triggers
http://aom.heavengames.com/cgi-bin/forums/display.cgi?action=ct&f=13,18204,,all) is that this one works
with units trained in game! [whisper]*yay*[/whisper] It also walk in MP, if you use
Army Deploy instead of
Unit create.
Step 1: Make the Bridge
To make a bridge passable, you'll have to start with a bridge of course. This guide was not made to show you how to make a bridge, so I'll skip that part. Just a litle *hint*: It looks best if it looks like it is a "tunnel" through.
Try this guide to make a good bridge:
http://aom.heavengames.com/cgi-bin/forums/display.cgi?action=ct&f=13,19183,0,all
Here is my bridge:

(Click on the pic to see my "tunnel" better)
Step 2: Triggers
This is the basic triggers to start with:
Trigger (Side 1): Active, loop, run Immidiately
conditon:Units in area ( this is on the side the ship is coming from)(Place a cinematic block as the center object)
- Player: 2
- Unit type: Trireme
- Radius: 6 (This matches the "gap" of my bridge. This must be customized to your bridge of course)
- Operator: == (Equal)
- Count: 1
Effects: Change units in area
- Radius: 6 (This matches the "gap" of my bridge. This must be customized to your bridge of course)
- From player: 1
- To Player: 1 (This can be anything)
- From type: Trireme
- To type: Cinematic block (As you might see, this will make the trireme disapear)
Unit Create (Army deploy for MP)
- Player: 1
- ProtoUnit: Trireme
- Area: The other side of the bridge
Disable trigger: Side 2 (DO NOT FORGET THIS)
Fire event: Move side 2
Fire event: Allow Side 2 pass
Trigger (Move side 2):Run immidiately
Condition:Allways
Effect: Move from area
- Center unit: Cinematic Block (On the side the ship is coming out)
- Unit type: Ship
- Player: 1
- Radius: 6 (This matches the "gap" of my bridge. This must be customized to your bridge of course)
-
Area: A bit away from the bridge ( On the side the ship is "coming out"
Trigger (Allow Side 2): Run immidiately
Condition: Timer: 2 seconds
Effect:Fire Event: Side 2
Of course you'll need two set's of each trigger - one for each side of the Bridge. All Area's/center units/points must be "mirrored" in those triggers
Additional Comments
To make this work with all kinds of ships, you'll need one trigger for each ship you are able to train. Those triggers are needed for all ships: Side 1/2, Allow side 1/2.
You'll need all triggers again for eventual water Myth Units.
You can have two ships passing the bridge at the same time - but only if they're coming from the same side. O ne ship from each side assing at the same time will not work, but thats logical aint it?
- Villi