Portal 2

Portal 2

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How to build a fun cooperative maze in the PeTI
By Muerte
This will show you the steps I took when making the Companion Cube Cooperative Maze maps.
Conceptual Ideas
If you have not tried it yet, play the levels that this guide is based on:

This is going to be a high level description of the process I went through to create these levels. I'm not going to go into the details on how to use the PeTI or Bee Mod, there are other guides for that, but if you are interested in how I made these mazes, read on.

First off, when making a maze, if you don’t provide a way to take a look at where you are, people will get frustrated very quickly. You may be a rat in a maze, but you can’t smell the cheese to find your way through.
The solution to that problem was to make two mazes and let the players guide each other. This keeps the player in the maze, but gives them a way to find their way when they are lost.

[Viewing the maze from the entrance]

Looking at the screen shot, the player can easily use their ping tool to guide their partner to any place that appears relevant because they can see most of the maze from their vantage point.
After play testing this concept I quickly realized if it was just a straight maze, it wouldn’t be a challenge and not much fun. After all, if the only cooperation was to point your partner in the right direction, you could take one look at the maze, solve it and be done. That is why there is also a series of puzzles to solve.
Building the Maze
So, let’s discuss how to build one of these mazes. The limitations of the PeTI, and what seems reasonable without getting frustrating meant that the maze grid should not go past 10x10. I originally tried to make a maze on my own but gave up. I’m not very good at it. So I used an online maze generator and made two mazes that I overlapped in Photoshop so I could make sure the end points lined up.

Then the next step was to translate that into the editor. After some trial and error, I realized I needed to convert it into a 20x20 grid that would match the editor’s grid. With one block for a wall and one block for the passageway.

Then it was a simple matter of going block by block and determining what to raise up and what not to.
The Entrance
The most important part of the maze is the entrance. It serves two purposes. First it allows the players to see the whole maze and make a decision about which side to take. It also allows them to see the exit on the far side so the know where their goal is. The other and most important part is to separate the two players into the top and bottom half of the maze. I use a trigger area at the top of the platform up that closes the door so the player can’t get back down and also to trigger the other platform to let the other player into the bottom maze. There are of course other ways to gate the players into separate paths, but I chose this method because it gives the players a sense of purpose and immediately drops them into environment.
With the maze completed, the next step was lighting. This one is tricky, because of all the twists and turns, there ended up being a lot of dark spots. Wandering in the dark isn’t much fun. Originally I started with all the surfaces being non-portalable, but that also proved to be not much fun and made for a very dark map. The solution was to place a ring of lights around the edge of the map, using both the light bars and the observation rooms. Then I placed a series of lights on the top of the bottom maze and on the ceiling of the top maze.

This provided an adequate amount of light, and changing all the surfaces except those between the mazes into portalable surfaces made it much more enjoyable. However, I remember from studying the commentaries of various Valve games, that lighting is also an important tool to guide players. So I started adding lights along the walls that would guide the player to the exit. It provides a subtle clue that they are moving in the right direction.

The Puzzles
Now it is time to add some puzzles to make the maze interesting and also give some landmarks for players to remember.
There are a few key points to remember when making a puzzle like this. First make sure that the activator and the end point you are affecting are visible from both sides. If you use a cube to block a laser to open a door, make sure you can see the door from where the laser is. If the player can’t see what they are changing, then they will get frustrated and might lose interest. Once the player has figured out that they have changed, it created a goal that they can direct the other player toward. This makes it interesting and fun.

The puzzles can be simple or they can require a few hoops to accomplish. In the second maze, there is a puzzle that requires using a portal to redirect a laser to activate a tractor beam, which pushed the cube onto a wall button, and then a timed button completes the circuit and opens the door.
I made use of the PeTI Bee mod that adds trigger areas and doors to accomplish the puzzles, this allows more flexibility in the puzzle without adding complexity.
Puzzle Issues
A few caveats to keep in mind.
First, never under estimate the lack of planning your players will do. So if they go through a door and don’t bring their cube, make sure they can get back. I used a trigger area next to the back side of the door, this way it opens and they can place a portal to get out.
Also, I found that by standing on the cube, the players could portal over the bottom level of the map. I toyed with making the bottom two cubes high, but that obstructed the visibility of the top maze. So I added the fizzlers to fix that.
That created the problem of possible cube destruction. So make sure there is a way to respawn the cube if that happens.

Other thoughts on Puzzles
When planning your puzzles, its best to put them off the main route to the exit. I like to keep it simple and only put one puzzle per zone. The first set of puzzles should open the first set of doors, one for each player and so on with the second and third.
I also place subtle hints to where the puzzle areas are. I used cool white lights along the main solution route as I discussed above, but I used the warm white lights on the walls to guide players to the puzzle areas. The upshot to this being that once you know what to look for, you can easily solve your puzzle without any help, but most people won’t notice but will be subconsciously guided by them anyway.

Remember the key to strike a good balance between the puzzles, the maze, and the difficulty so that players will get a thrill when they solve one part of the maze, which will motivate them to solve the next part.
Final thoughts
I hope this helps anyone making maps or mazes to avoid some of the pitfalls that I experienced while putting these maps together. Just remember to use lighting to guide your players, and keep the goals easy to figure out. Most of all, play test your map with as many people as you can, and remember if it isn’t fun, then make the hard choices to fix it.
Good luck and happy mazing.
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Muerte  [author] Jan 30, 2014 @ 8:52pm 
In order to prevent the top player from turning around and coming back down, yes because you can not place the walk through triggers without Bee Mod. Also the doors look much better with Bee Mod verses the panels. With some clever tricks you might be able to get around that with the vanalla editor, but it would be much more difficult.
Nobuhiro Takeda Jan 30, 2014 @ 6:13pm 
do you haft to have a bee mod or what
✭ Happy_killer ✭ Jan 28, 2014 @ 11:41am 
Turtle Pokeout Jan 25, 2014 @ 11:27am 
Роман Jan 22, 2014 @ 8:40pm 
TheFelineOverlord Jan 20, 2014 @ 6:54pm 
awesome guide man!
The Muffin Man Jan 16, 2014 @ 12:01am