bobobologna on 21 December 2009
You have to use a magnetic switch.
So have the piston linked to the magnetic switch located in another part of the map. Create a magnetic key above the magnetic switch and separate the two with a destroyable block. Then create button that the player can activate to destroy the wall.
So the magnetic switch won't activate, and the piston is at minimum length. The player pushes the button, the block is destroyed, the magnetic key falls and activates the magnetic switch. The piston extends to maximum length. As long as nothing happens to the magnetic key/switch, the piston will remain extended.
At least, that's how I think you do it. I don't own LBP anymore, and haven't played in a long time.
