Hi I hope I'm posting this in the right section, if not, I apologize.

I have to make a Use Case Diagram for a game proposal I made ages ago, the only thing is I don't really understand them, like at all.

My game is just a Legend of Zelda 1 clone with grid based movement similar to Startropics and Pokemon Red.

I am required to do:

1. A list of functional Requirements with descriptions.
2. A Use Case diagram
3. A Use Case description for each Use Case on your diagram.

I don't really understand use case diagrams, I sort of get the ATM one but I don't think they work well for games. DO I need to make a different diagram for every aspect of the game or do I need to make one big one?

Also do I have the actor be the player and have all the conditions be button inputs. Or do I have the actor be the player character and have all the conditions be actions like "jump"?

I don't expect ye to do the whole thing for me, I want to learn but I don't understand examples because very few cover games.

If you could just do a small example based off my proposal to help me understand it, I would really appreciate it, thanks.

Ok thanks for both your help

Hi I hope I'm posting this in the right section, if not, I apologize.

I have to make a Use Case Diagram for a game proposal I made ages ago, the only thing is I don't really understand them, like at all.

My game is just a Legend of Zelda 1 clone with grid based movement similar to Startropics and Pokemon Red.

I am required to do:

1. A list of functional Requirements with descriptions.
2. A Use Case diagram
3. A Use Case description for each Use Case on your diagram.

I don't really understand use case diagrams, I sort of get the ATM one but I don't think they work well for games. DO I need to make a different diagram for every aspect of the game or do I need to make one big one?

Also do I have the actor be the player and have all the conditions be button inputs. Or do I have the actor be the player character and have all the conditions be actions like "jump"?

I don't expect ye to do the whole thing for me, I want to learn but I don't understand examples because very few cover games.

If you could just do a small example based off my proposal to help me understand it, I would really appreciate it, thanks.

I agree with @TheChubu, it depends.

You could model, for example, how the player interacts with the shopkeeper in an item store, or the navigation of the inventory system (e.g. equip/use/discard item).

I really like this introduction to UML. It's simple, clear and concise.

I draw UML diagrams with Violet when the need arises.

I am required to do:
1. A list of functional Requirements with descriptions.
2. A Use Case diagram
3. A Use Case description for each Use Case on your diagram.

Who is requiring it?

A teacher? In that case, consider asking your teacher for clarification.

I really don't imagine any other group asking for such a thing. Requirements documents and use-case examples are really only useful for communications and not so much for implementation.


When I think of use cases and requirements I imagine short design documents. I can easily imagine this because game objects often have 2-4 page descriptions and use case examples.

Since this is completely unrelated to your Zelda-style game, I'm hoping it will be useful enough to serve as an example but useless enough that you cannot turn it in. I worked on a locking door in The Sims. (Useful link so you can see what actually shipped). The requirements basically were described like this:

The object is a turnstile door. Variations include a half-height turnstile gate, a full-wall turnstile gate, and a full-wall solid door.

{Assorted pictures from the Internet suggesting an art style}

The player can click the door to select what kind of locks they want to set, or clear locks that are already set.

Locks should include:
* Ticket holder {red, green, blue, yellow tickets}
* Lock based on gender
* Age older than {toddler through adult}
* Age younger than {child through elder}
* Age exactly {toddler through elder}
* Lock based on occults, listing any installed occult type (vampire, zombie, fairy, mummy, etc)
* Lock based on species, listing any installed species
* Lock based on celebrity level, if celebrities are installed
* Any other lock that programmers can think would be easy to include
* Future-proofing to include new features in the next few expansion packs if possible

The UI is flexible. The menu to handle all the locks might look like {picture}, but we are planning to try other options based on feedback. The programmer has agreed to try several variations, and allow up to 3 days in the schedule for design and production to attempt additional variations.

Then there is a roughly 15 line checklist description of the typical behavior. If a player would be blocked by the rules, the player should attempt a different route rather than being blocked. Player walks to the door. If the only criteria they are missing is a ticket, they will automatically buy the ticket. If they meet the criteria a light appears, a sound is played, and the door opens. If they do not meet the criteria the red light stays on and a rejection sound plays. Emergency workers and critical services should be permitted through the door. Etc.

Additional notes: From various discussions, we allow people to be locked in the room indefinitely if the player changes the door locks or the sim somehow changes criteria, such as aging up. If the programmers can figure out an easy way for people to escape when locked in during a fire or other emergency that is fine, but if the sim is trapped and dies that is fine too. This is a story-telling object, so if you can find a good way to limit contradicting locks that is nice, but not required. It would be nice if we prevent doors that lock everyone out, but since both our QA and our programmers keep reminding me that we have an impossibly-high number of combinations to test, focus on what is funnest for the players with as many comprehensive spot-check tests as possible.

Use cases:

Firefighters, police, thieves, and other critical roles are always permitted through the door, no matter what the settings.
You can build a room that allows anyone.
You can build a room that allows only family members. Everyone else is rejected.
You can build a room that allows only the active player. Everyone else is rejected.
You can build a room that allows any young man and also the active player. Everyone else is rejected.
You can build a room that allows old women and allows kittens. Everyone else is rejected.
You can build a room that allows teenage girls, allows male teenage vampires, and allows male teenage werewolves. Everyone else is rejected.
You can build a room that allows male adults, female celebrities, and bartenders. Everyone else is rejected.
You can build a room that forbids zombies. Everyone else is permitted. (Surprisingly useful with Sims Supernatural.)
You can build a room with a regular door and a locked door. When an actor would be blocked by the locked door, they should choose the regular door instead.

The end result is something that programmers, modelers, animators, and audio know how to develop, QA can create pass/fail tests for, marketing can plan to sell, and any external group can read and understand the requirements.