Tricks: Walls and objects that can be walked through
Walls and objects that can be walked through ("transparent" walls/objects) is a trick that many Wolf3D level designers know already. There are 2 main ways of doing it:
- For walls, if a dead guard is placed inside a wall, the wall can be walked through. While this is the easiest way for transparent walls, there are a few disadvantages to using this method: 1) blocks can't be pushed through the wall, because blocks can't slide over dead bodies 2) dead bodies are "actors", and you can only have a maximum of 150 actors (including the player) on a level, and 3) if you look very closely at the wall, from certain angles, you can see tiny bits of the dead body poking out of the wall. This gives the transparent wall away.
While this is the easiest way of having transparent walls, it won't work for objects, because both objects and dead guards are object codes, so you can't put dead bodies inside an object. (Not initially, anyway.) Also, because of what I mentioned in 3, the walls are given away to clever players. Because of this, while this method is often OK for cases where it's not necessary to hide the transparent wall, it's often good to use alternate methods if you can.
- Another way that you can have transparent walls (this will also work for objects,) is to place a patrolling guard right next to and facing the wall/object. The guard will walk right through the wall/object and continue out the other side. After this, the wall/object will be transparent, because any tile that an enemy walks on is made penetrable when the enemy leaves it. Note that this method will ONLY work if the guard initially walks through the wall/object. Patrolling guards will only walk through a solid tile if it's the first tile they walk onto. Otherwise, they'll be stopped by the tile and will appear to walk in place.
While the first method is the easiest way of making transparent walls, the second method is preferred and also works on objects. Transparent walls and objects can be used for many different things, including hiding secret areas. If a block goes through a transparent wall, it will eat away the wall.
One other thing: You can also have doors that can be walked through. To do this, place a patrolling enemy inside a door and make the enemy walk out of the door and into a holding pattern. Take note, however, that if the door is opened and closed, it will become solid again when it is closed. To make the side of a door penetrable, either use one of the above methods or just assign a floor code to the door side tile. If you do the latter, there will be a phantom "non-shaded" gray stone block (discussed later) in it's place that can be walked through. If you'd like the door to not even have a side block at all, assign the "deaf guard" floor code to the side tile of the door (no, this WILL NOT make the door "invisible".)