• Ray

Designing Character Traits in The Sims 3

Updated: Sep 12, 2019


(First to last: A Hopless Romantic Sim; An Evil Sim; A Great Kisser)


In The Sims 3, we made many additions and improvements to the lovable and quirky beings we call Sims. By far, my favorite of those is our character traits system, and I know I’m not alone – it has captured the hearts and minds of our players, too – often even more than our largest feature: the seamless, living neighborhood. So I wanted to describe the thinking that led us to the traits design, and some of the interesting choices and observations we made along the way.


Personality in The Sims and The Sims 2


First, a little background. In The Sims and The Sims 2, personalities were chosen on a ten-point scale along five different personality characteristics:

(Personality Chooser in The Sims, then The Sims 2)


In The Sims, personality affected the choices a Sim made on their own, affected rates of skill gain, and also altered the speed a Sim’s needs would deplete. For example, a Sim with a high playful score would have their fun drop quickly, causing the Sim to do more fun things than normal.

In The Sims 2, we expanded the system to add special behaviors for specific ranges of personality. The 0-3 range was considered “low” and 8-10 points was considered “high.” Both came with unique animations and interactions for the Sims. Anything in between (4-7 points) was considered neutral, and usually did not have any special animations or interactions. For  example:

  • Sloppy Sims (0-3 points) would create puddles when taking showers, make objects dirty more quickly, and could eat from the trash.

  • Neat Sims (8-10 points) could get fun by cleaning objects, and could even clean objects that weren’t yet visibly dirty, causing those objects to take much longer to get dirty.

  • In Between (4-7 points) didn’t have special animations or interactions. They only had varying need decays, skill rates, and autonomy behaviors. 

All personalities worked this way. As you can see, we bundled the special content toward the extremes.


Inspiration and Philosophy for Traits


The problem we found as we were implementing personalities on The Sims 2 was that we couldn’t reasonably create enough special animation and interaction content to make each notch of the 0-10 scale feel interesting.

Additionally, players didn’t understand that there would only be a nominal difference between, say, a 2-point and a 3-point Sloppy Sim, but a huge difference between a 3-point Sloppy Sim and a 4-point Sloppy Sim. We didn’t make that clear in the UI, so players had to learn this from strategy guides and Sims wikis.

Around the time we began designing The Sims 3, I’d been reading a lot about screenwriting, and noticed that in screenplays, characters often have a few glaringly distinct traits. There’s no fuzziness about them:

  • Tyler Durden: Stylish. Leader. Unrestrained. Monster. Rebel.

  • Han Solo: Laid Back. Arrogant. Jealous. Street Smart. Rebel.

  • Hermione: Friendly. Know-it-all. Mudblood.

  • Patrick Bateman: Clean. Ritualistic. Egotistical. Obsessed with Business Cards. Murderer. 

  • The Dude: Stoner. Low Key. Loves White Russians.

  • Marry Poppins: Excellent Nanny. Flies. Sings. Has Magic Bag.

We used this approach as inspiration on The Sims 3, and developed a philosophy of doing away with the continuous aspect of personality. Instead, we wanted to take the extremes from The Sims 2 and package that fun content into discrete bundles of behavior, which we dubbed Traits.

A Friendly Sim (probably waving to Bella : )

Scouring the Personal Ads (For Science!)


Now, how would we begin to figure out which traits we wanted? One of the first days we brainstormed traits, my boss called me into his office. Quirky genius that he was, he sat me down and pointed to his monitor, which was littered with personal ads and dating websites. The idea was to see exactly how people described themselves. People said things like the following, which are from real personal ads:

  • Proud

  • Loves Poetry and Chocolate

  • Down to Earth

  • Enjoys the Outdoors

  • Passionate

  • Romantic

  • Appreciates Classical Music

  • Athletic

  • Walking the Fine Line between Human Being and Deity

  • Articulate

  • Friendly

  • Trustworthy

  • Mid-Life Crisis Sufferer

  • Non-Smoker

  • Smoking Enthusiast

  • Penchant for Whistling

  • Likes Kissing

  • Reclusive

  • Adventurous

If you play The Sims 3, you’ll notice some of these from the game with slightly altered names: Loves the Outdoors, Hopeless Romantic, Athletic, Friendly, and Loner. And although Mid Life Crisis didn’t make sense as a trait, we used it as a lifetime happiness reward which could be used to swap traits mid-game.


Seinfeld, The Simpsons, and Arrested Development


Then we locked the design team in a room and made a list of the interesting characters we knew from TV, movies, and books. We filled entire whiteboards with names, then scrawled the prominent traits of those characters in any whitespace we could find. Due to the wonders of technology, I was able to dig up a piece of one of those brainstorms. I know it looks like we had an angry chimp scribbling these down, but hey… it’s hard to keep a chimp happy all the time:

One segment of a whiteboard brainstorm of characters and their prominent traits, circa 2005. (Note that there is no spatial relationship between the traits and the characters – we were cramming stuff in everywhere.)

In the end, a handful of fun traits in The Sims 3 were inspired by some of our favorite characters. Here are four:

An Evil Sim, scheming about pool ladders, sharks, and laser beams.
  1. Frugal and Mooch: For both of these, we had George Costanza in mind. Remember the episode where he insists on the cheapest wedding invitations in the store, and his fiancée dies from licking the cheap toxic glue on all the envelopes? That’s Frugal right there. 

  2. Evil: Mr. Burns from The Simpsons inspired us, right down to his finger-drumming. What’s not interesting about a guy who decides to erect a giant sky-disc to block out the sun from his town?

  3. Never Nude: Later on in production, Grant Rodiek, Ryan Vaughan, and I became obsessed with the show Arrested Development, which led us to the Never Nude trait. We still think Tobias Funke is one of the funniest characters of all time.


Traits for Gameplay Systems


As we fleshed out the designs for the rest of the game, we continued to add traits that enhanced the gameplay of those systems.

As we designed Fishing Skill, we added the Angler trait – these Sims are natural fishers and have lots of fun while fishing. When designing Gardening Skill, we added Green Thumb – these Sims are great at gardening, and can even revive dead plants. And as we developed the food system, we added Vegetarian – these Sims get special versions of recipes, like Tofu Dogs, and they enjoy longer lives… but be careful: force them to eat meat, and they’ll start throwing up (players always enjoy new ways to torture their Sims!).


A Green Thumb Sim

Trait Controversies


Then, there were some traits that were hard to agree upon. Do we want them? Do they fit the “Sims” style? Do they provide enough value? Here are the stories of three troubling traits: Clumsy. These Sims drop food, trip over their feet, tumble into pools, and generally lack coordination. The trouble with Clumsy was that it had no gameplay value. Some designers wondered why anyone would pick a trait that had no benefits. On the other hand, the argument was that Clumsy would be worth it just for the humor and storytelling aspects. In the end, we shipped it, and many players loved it, often saying that they themselves were clumsy, and so they felt a special attachment to it.


An excitable Sim! It’s so exciting!

Kleptomaniac. These Sims have the ability to steal objects when nobody is looking. We knew the gameplay for this trait could be fun, but had a hard time agreeing on whether it had a home in the Sims universe. Sure, we’ve had burglars before. But was it okay to give players the control to steal things with their Sims? We typically avoid dark subjects. In the end, we shipped this trait with the fiction that these Sims couldn’t help it. They weren’t bad people, they just needed to steal. And players couldn't tell them what to steal -- you could only tell them to Swipe Something, and they would grab something random in the room... it could be a stereo, it could be a painting, or it could be a used toilet! We also gave them the ability to return stolen items to make amends with the victim. Kleptomaniac ended up being an incredibly successful trait that helped tell some interesting stories and create funny conflicts.


Excitable.  These Sims were in the same boat as Clumsy. All they did was get super-excited often, without gameplay benefit. But it was so much fun to have your Sims get excited about everyday things as mundane as checking the mail. (Excitable is actually my favorite trait.)


The Great Merge


Eventually, we had a list of over 100 traits. Far too many. It would have been an overwhelming list for new players to wade through, and also too much to implement. First, we ruthlessly cut the weakest traits. That left us with traits that we liked, but many of them didn’t have enough gameplay, or were too similar. This led us to “The Great Merge,” where we combined a lot of our proposed traits into fewer, stronger traits with more gameplay. This eventually got us to The Sims 3’s shipping set of 63 traits.

For example:

  • Scientific + Genius + Gifted ➔ Genius

  • Angelic + Good ➔ Good

  • Bully + Mean ➔ Mean

  • Creative + Artistic ➔ Artistic

  • Confident + Brave ➔ Confident


A Genius Sim doing some calculus in the air.

Five Traits, Period.


We limit each Sim to a maximum of 5 traits. Early in pre-production, this wasn’t the case. We originally had a system where each trait had a point value, and the player had points to spend. Positive traits cost points, but negative traits returned points as an incentive to pick them, thereby allowing players to choose many traits as long as they balanced negatives with positives. But we quickly realized this approach was far too geeky and inhuman for a Sims game.

Next, we tried removing the points, and just letting players pick to their heart’s content. And that’s just what people tended to do – pick lots of traits. There’s a reason movie characters only have a few big traits – too many and it waters down their identity. We found the same thing happening in our prototype. Ultimately, we settled on a maximum of 5 as a number that was still large enough to give virtually unlimited interesting combinations, yet was small enough that each trait felt like a meaningful choice.

Also, it’s easy for players to remember 5 traits, as opposed to 7 or 10 or more. When a player can remember a Sim’s traits easily, they are more likely to change their play style in accordance with those traits – e.g. My Sim is a Virtuoso, I should practice guitar today or play in the park for tips! That’s the kind of trait-based motivation we want to see! We settled on this number even before production. You can see the space is limited to 5 trait slots in this screenshot of our 2D prototype. Testing these variations in our prototype saved us plenty of UI re-work we would have had to do if we’d learned these lessons later in production:


Our Sims 3 “Living World” Prototype, with the Create-A-Sim screen showing our 5-trait limit. This prototype helped us learn the right approaches to features like traits early on while the lessons were cheap, rather than later in production when they would be expensive.

And in the final game, it looks like this:


Looks Trump Character during Creation


We wanted to emphasize character, so we considered having traits as the very first part of Sim creation, even before the appearance of the Sim. It was a well-intentioned, but ultimately doomed idea.

We quickly learned that most players don’t even think about the internal character of their Sims until they can see the visual character. If we gave them a random Sim and opened up the traits panel, they wouldn’t pay attention to the traits – they’d feel like they needed to change the look of that Sim first.

In the end, we ordered Create-A-Sim from the most prominent physical characteristics to the least (first gender, weight, & skin tone; then hair; then face & makeup; then clothing) followed by traits. It’s interesting to note that the hair step is even before face; this is because hair makes such a huge difference in visually defining a Sim – more than setting any aspect of a Sim’s face (especially from a larger viewing distance).


The Most Popular Traits


Here are the 4 most-chosen traits:

  1. Friendly

  2. Athletic

  3. Great Kisser

  4. Family-Oriented

A whopping 8% of created Sims have the Friendly trait -- yes, 8% is high when there are 63+ traits to choose from, and not all Sims leave Create-A-Sim with 5 traits (younger ages get fewer). Almost as many Sims have AthleticGreat Kisser, or Family Oriented. I love the uplifting message this sends about our Simmers – our community idealizes positive, wholesome qualities in humanity! (With a little smooching tossed in.)


A Family-Oriented Sim, gazing at her family.

We learned a strong lesson from seeing Great Kisser in the top 3. This was one of the traits surrounded by controversy about whether it had enough gameplay value to warrant its existence. All it did was give your Sims better chances of having their kisses go well with other Sims. It’s not actually a big advantage. In the world of strategy gaming, this would be a poor choice. However, Sims games don’t find their places in players’ hearts because of the strategy – instead, it’s all about the creativity, fiction, and storytelling power – and this is why Great Kisser is so popular.

Players are mostly picking traits based on the fictional character they are trying to make and not focusing on gameplay benefits as often. 


In other words, they’re picking the words that best describe themselves, their ideal selves, or the people they are trying to make. Great Kisser sounds awesome. Traits don’t have to have large benefits (or dev time sunk into them), but rather, they need to appeal to a player’s imaginations and aspirations first.


A Case for Negative Traits


Here are the 4 least-chosen traits:

  1. Unflirty

  2. Technophobe

  3. Loser

  4. Hydrophobic

It’s no surprise that the negative traits were the least popular. Unflirty was chosen less than 0.25% of the time. After seeing this data, I often get the question about whether we should have not had negative traits. After all, what was their use if so few people pick them?

There are a few good reasons. First, they are necessary to create a diverse and challenging set of personalities for the NPCs in the town. If everyone was easy to flirt with, what fun would that be? So there’s the occasional Unflirty Sim to throw a wrench in things.

Second, they can be useful in describing people we know and want to make.

Third, it allows advanced players to create more interesting challenges. Try the Legacy Challenge with a Sim who Dislikes Children, is a Loner, and Insane! And as much as possible, we tried to add benefits to the negative traits in case players decided to check them out. For example, an Unlucky Sim may burn her home down more often and get the short stick in life, but if she dies by accident or malpractice, the Grim Reaper will feel sorry for the poor Sim and resurrect her.


A Lost Trait

A Vegetarian with her trusty eggplant.

We couldn’t implement every trait we wanted, so I thought I'd share one of my favorites from that cut list. It's the Colorblind trait, which I thought would be super neat (and educational). The idea is that the player would have been able to pick a type of colorblindness for their Sim, and then when that Sim was selected, the game would use a shader to render the screen as if through colorblind eyes. Similar to this website that renders any web page (like Google) as a colorblind person would see them. A new way to see through your Sims' eyes!


A Final Word on Traits


Character Traits ended up being a very fun, easily extensible system that we’ve had a great time supplementing with each expansion. (Even before The Sims 3 released, the concept of traits as an evolution of character was exciting enough that it inspired The Sims 2 team’s pet-personality system for The Sims 2 Pets.)


The movement from an analog personality system to discrete bundles of behavior gave us and players a creative toolbox to make millions of inspiring, deep, dramatic, and entertaining characters. 

And they are The Sims.



PS – To the huge number of you who wrote comments, I had to archive them when I moved my site to a new host. Thank you for the 8000+ words of discussion, they are not lost... just not here : )