# Transitioning from Linear to Open World Design with Sunset Overdrive

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When it comes to game design there are two main types of level design, linear and open world. This week at GDC 2015, Insomniac Game's Designer, Liz England spoke about what it was like transitioning from Insomniac's typical linear design to an open world in Sunset Overdrive. Insomniac Games has been a game development studio for 20 years, and in those years they have produced a lot of games. There is one thing that almost all of Insomniac's games have in common, they have really linear gameplay. When Insomniac transitioned to open world in Sunset Overdrive they experienced many challenges and were able to adapt to them, and end up with a well constructed experience that was out of the norm for their typical games.

### Linear vs Open World

During the talk Liz began to go into further detail on how she explains the difference between linear and open world gameplay, "If I were to give you a piece of paper, and tell you to draw me a linear game structure you might come up with a series of lines where A goes to B and B goes to C and so on. It's a deterministic order, if you want to go from A to C you always have to go through B first." She stated, "If I were to tell you to draw an Open World game structure it might be a little more difficult, but it usually looks like more of a spiderweb. So you can go from A to B to C again, or you go from A to D to C and then back to A. It's not deterministic, you don't always know where the player is going to be, or where they are going to go next, unlike a linear game." In a linear game if you know where the player is you can get a lot of information about the game state, and in an open world game you don't really have a lot of information about the rest of the game. With open world the game state is just a lot of unsolved variables. Another example of a linear game would be the more obvious one, a book. If the reader is on page 200 you know what they've read to get to that point, and you also know what they have left to read. Alternatively if you have a none linear reading material like a Wiki page, just by knowing what page the reader is on you don't really know what pages they've already read, or have yet to read.

### Role of Designers on Sunset Overdrive

Liz also explained how the each designer worked on Sunset Overdrive, "The design generalists became design specialists, instead of the designers being responsible for all the different kinds of content, we would split it up. On Sunset Overdrive the designers owned systems, and each designer was responsible for a specific system. I would describe this as a vertical versus a horizontal structure. Vertical would mean each designer has their level and all the gameplay in that level, and that would be our linear type games. In the open world game each person would have a system across all the levels." She went on to explain a system more in-depth, "A player is moving through a space, they are traversing, that would be the traversal system. Then they're fighting enemies, that would be the combat system, when they complete an objective that would be the mission or quest system. There wasn't necessarily one designer responsible for each system, but there might be 3-4 designers on the combat system." With a linear game, the designers would typically be responsible for a specific area in the game, and they would handle every area of the design, mission design, puzzles, level design, etc. The only thing they would need to worry about his how it fits with the level before, and the level after.

### Workflow

The workflow between a linear game that Insomniac created like Resistance 3 versus Sunset Overdrive was a bit different and Liz explained how, "On Resistance 3 we started out with a designer, and all designers owned physical chunk of the world, so I might be responsible for three levels and two systems, and the systems might be like doors and combat, and someone else might own co-op, and someone else owns objectives. I work with the gameplay programmers to create the systems and figure out how we're going to implement it." On Sunset Overdrive the workflow changed slightly, "The designer defines the system and works with the gameplay programmer to create the system and then they implement it across all the spaces." In Sunset Overdrive they don't start with the designer, they start with the specialists now. So they start with the world builder and the world builders were traversal designers because traversal and level design were paired very closely together. Liz continued, "Our world builders white boxes the spaces going back forth with the other departments, and then they would add this thing called a traversal layer and that is just basic traversal objects. The other half of the traversal layer was marking out the critical path. In a linear game that path is not a straight arrow, it's jagged but it's still going to go in one direction. In an open world game this path is going to be a spiderweb. So in the levels we actually had these spiderwebs of yellow arrows moving through the space and that told you what the paths were in and out of that space. The traversal designers or world builders are looking at this at a very high level point of view, they're white boxing the cities and creating that traversal that gets the player to move through those spaces." While Insomniac games switched their designers from Generalists on Sunset Overdrive to Specialists which focus on one system within the game, whether it's combat, quests, traversal, etc. Liz stated that this is not a permanent change, on Insomniac's part, it was how they adapted to creating an open world game. Depending on the type of game you're creating a generalist designer who creates everything in their designated area, including the paths, the quests, the layout, etc. may work better.