Situation: Whenever I invade another player's island, I set up like 5-6 military camps around the trade buildings to capture them. After waiting a loooong time, when the timer hits 0 and the ownership is meant to be given to me, they instead collapse and disappear. WTF? How do I stop this and get to keep the buildings? It's making taking over islands extreeemely slow since the NPC just builds a new warehouse straight after.
It sounds like the enemies are razing the building in order to keep you from taking it over. I'm not sure if the likelihood of this increases with the difficulty you're playing on, but in case it does, you may want to try lowering the difficulty.
In order to increase the speed of takeover, I wouldn't rely on trade building capture being your only method. Here are a few steps you can take to speed it up.
- If you have enough resources, upgrade your Castle to a Warehouse. If you're having trouble taking control of the island, then establishing a Warehouse will benefit you greatly, as you can store your goods and start establishing markets with those goods. In addition, you should stock your strong box with items that will increase your military's effectiveness.
- Build an Oriental Forts and Assassin's Camps so you can produce units which will have bonuses for capturing.
- Use trebuchets and cannons to make holes in walls so your land units can move around easier.
- If you're playing on Easy or Medium, you can tear down enemy buildings in your influence area to provide yourself with more materials.
- Blockade enemy warehouses/castles.
- If you're not concerned about having to rebuild homes, then set it all on fire. Take out the fire stations, then use trebuchets/cannons to wreak havoc.