Usable, Legible, Believable - Interview with Tom Cartos

I sat down for a chat with my buddy Tom Cartos, one of the most prolific TTRPG cartographers in the third-party space. I've known and worked with Tom since 2019, but it was great to get a chance to dig deep regarding his workflow, his cartography priorities, and his new Kickstarter. Tom is a former architect who thinks about his mapmaking quite differently from many of the other cartographers in this space, and that really shines through in his maps.

If you're interested in Tom's work, please show his Kickstarter and his Patreon some love. This is not a sponsored post.

Will Savino: This is a comically broad question: what makes a good map? To you, to a GM, to anybody?

Tom Cartos: What makes a good map? I think what makes my maps good is they are usable, they are legible, and they are believable. Those are the three things I'm always trying to balance.

So, “usability” obviously largely comes down to gameplay. Is there space for all the players’ tokens or minis to move around each other and do what they want? Are there strategic areas for battle? Interesting hurdles or obstacles, things that break line of sight, different sized spaces, that kind of stuff?

“Legible” is just purely like, if the players are looking at it, the GM's looking at it, do they know what that thing is on the map? Or are they just kind of guessing if it's a blob?

And then “believable” or “realistic” is just: does this space make sense? Can you imagine real people using this on a day-to-day basis in a way that you would expect? If you walk into a house, are all the rooms there that you would expect to be there? Same if you're in a, y’know, a torture room in a dungeon. Are all the devices there that you would expect?

Will Savino: I want to talk about all three of those things in greater detail. Not gonna lie, I didn't expect you to have such a bullet point perfect answer to that. But it totally makes sense, given your map style, that those are your top three priorities.

Going in reverse order:

I think one of the reasons that I assume so many of your maps just seem to make intuitive sense is because you have an architectural background, right? There are a lot of times where we're [i.e. the Borough Bound team] making maps and it's like, wait, how is that holding up? Are we cantilevering that? Is that a structural beam there? I don't really know how important a lot of that stuff is. It probably depends on the GM.

But with your maps, you’ve always thought about: where are the doors? where are the corridors? how does everything actually line up? if you were to walk from one space to another, is that how a space would actually be designed? It seems as though you are thinking deeply about each of those questions.

Tom Cartos: Yeah, I mean, I don't know “deeply” is the right way to describe it because it's more just intrinsic in the way I work. I've done it for so long in that way. That's how I know how to plan a space. What are the areas I need? How do they connect to one another? And how does that work around a general structural system that at least looks like it makes sense? And one of the best things about doing battle maps instead of real world stuff, is it doesn't have to actually work. It's enough if it just kind of looks like it works.

But I think that does really help with the level of immersion, in that if a player can see that the top level of part of a building is just held up by a column, they can knock that column down and the building falls down, and that's an extra opportunity in the battle that they may not otherwise consider.

Will Savino: There's a tricky bit with “realism”, where… you know, there's the classic example of redditors complaining about lack of bathrooms or chamber pots, whatever, depending on the era. And when our art director, James, and I are working with Matt—who does our interior maps—we often run into these situations where we have a building set up, we know what the cool points of interest are going to be, what the set-piece locations are for encounters that we expect GMs to have.

And then we sort of have to think, “okay, well realistically you know there'd be the storage space. Realistically, you'd probably need some sort of backdoor even though that kind of makes this a bad dungeon. Realistically, oh god, you wouldn't even design it like this because you'd need more windows or you'd need better ventilation or how many chimneys would we need if there were etc., etc...” And sometimes it feels as though that's getting in the way of us making a good map. Is that just our fault?

Tom Cartos: No, no, not at all. There's definitely always a balance to be considered. I think that's something I've got better at over time. I'm sure if you look at some of my old maps you'd wonder “why are there so many toilets in here?,” and it's because I'm thinking, well, “what is the potential occupancy of this building, so how many bathrooms?” and that just doesn't really matter.

It's not going to be an issue if all of your kobolds are queuing up to go to the bathroom or whatever in a fantasy game. It’s about it looking believable more than it's about it being realistic. And, no matter what you're doing, there's always going to be someone who is a bigger expert than you on that specific thing. Especially now that I do modern content as well. There are people who actually work in things like civil engineering and health and safety who'd be like “you haven't got enough fire exits here," or "your stair risers are too high," or "you don't have enough elevators here.”

That kind of stuff where you just laugh along with it and say “thanks for the engagement, thanks for boosting my post,” and you move on with your day. It's about making it look believable more than it is about making it actually real.

It's about making it look believable more than it is about making it actually real.

Will Savino: I want to talk about legibility. Your point is that, with Tom Cartos maps, you look at it and you know what everything is: the assets that you use and anything that you're creating from scratch. It always is, “oh I can tell that's a brazier, I can tell that's a toilet,” whatever. It's very easy to understand every piece of the map, and that is helpful for both GMs and players… probably even more so for players, because as soon as they stick their tokens down, they know what is interactable and how.

I think that there are mapmakers who strongly favor an almost totally opposite philosophy. You look at some maps by Czepeku or Stained Karbon Maps. They want to put tantalizingly weird stuff into the map and a GM has to either decide for themselves, “oh, this is some specific magical thing from my campaign,” or it invites the GM to give the players agency to state or declare what a thing is. Do you think that there's any merit to a philosophy like that?

Tom Cartos: Yes, absolutely. It's great you're pointing out other mapmakers, and it's wonderful there are so many mapmakers in the space who have their own style and way of doing things, because there are so many GMs and players who have their own style and way of doing things. And I'm not trying to appeal to everyone. I think this is specifically what I'm good at. So GMs who are looking for that know that they can come to me for it.

My ethos with everything I do is “what is going to make the GM's life easier?,” because we all only have so much time. Game prep is already potentially a big burden on the GM. A lot of GMs do it because they love it, but if I can speed that up by deciding what's in every room—by just showing them what's in every room—then they don't have to make that decision. If they do need these additional specific things, there's only one extra thing they have to place or find an asset for, whereas everything else is already set up for them. 

Will Savino: I was talking to Wythe Marschall who creates Stillfleet, and he particularly loves abstract maps, because you can pull a move like: players walk into a space and the GM says, “okay. Every player, you name a thing that's in here.”  There's a lot of power in that, but it also is such a different way of playing the game than I think most people are used to, especially those who came into this hobby listening to Critical Role, where there's this notion that this is pretty prescriptive, right? The GM is going to tell you what's there, or the GM is going to look at the map, and then tell you, “yeah, if you see a book in the map, that book is in the map. And if you ask me what it is, I have to tell you what it is.”

Tom Cartos: Yeah, definitely. Also I think video games are such a huge aspect of tabletop game design as well, and there's such a massive crossover with players and audiences. People are so used to walking into a fully 4k rendered environment with all these interactable objects that you can see and tell what everything is. And also where I get a lot my inspiration and ideas from is through video games, so I think that comes through in my design.

But equally, with my maps, I always do a version without all the assets on them, and all my assets are individual files that I provide. So if GM wants a completely empty room, they can ask the players what's in this room, they can drag and drop it from my asset library, and set that up themselves. So the option is there it just takes a bit more work.

Will Savino: Perfect plug, obviously. 

Tom Cartos: [laughs]

Will Savino: And then in reverse order, the last thing—or the first thing that you mentioned—was usability. There are so many mapmakers in this space who make beautiful maps. Great colors. Compositionally, they look really nice at a glance. Maybe they even do particularly well on social media… But maybe you can tell that the cartographers are not frequently GMs or players in actual games, because you look at these beautiful maps and you think, "that would be boring to do combat upon," right?

I think a lot of cartographers are not thinking in any meaningful way about choke points, lines of sight, or all of these more fun aspects of what can make a map—even one that looks simple!—extremely tactically compelling. That's one thing that's great about your maps. Those really micro aspects can make a map stand out, because every player remembers that time that they used stealth to line up the perfect 20x20 cube or whatever and roast all their enemies alive without being seen.

Are you thinking about a specific rule set? Are you thinking, “oh in D&D, y’know, most characters can't jump 20 feet,” or is it just, “hey, I've played video games. I know what good level design looks like.”

Tom Cartos: I try not to be too specific with any one rule set, although I do deliberately make sure that all chasms are more than 35-feet wide so you can't misty step them. 

Will Savino: [laughs]

Tom Cartos: Otherwise, no. 

So, you'll notice when I mentioned my three things I think are important, I didn't say it needs to look good. Hopefully, hopefully, my maps do look good—I don't think they look terrible!—but certainly a lot of the other mapmakers have come into this from an art background, which I have not. I have no formal art training, other than just kind of what I figured out myself. A lot of people assume that architects are all beautiful artists who can hand draw. Absolutely not the case. We largely learn to draw in CAD with straight lines and rulers and stuff, which is how I sketch out my maps. I'm not creating a composition, necessarily, although I try to keep it somewhat in mind in terms of balance and what's just interesting to look at for potentially four hours while you're having combat.

My layout is things like sightlines and level differences and trying to just put in those strategic elements.

Will Savino: We've collaborated a few times, you and Borough Bound. My favorite map that you've done with us was Thestwick Watch Ruins.

This is such a cool map because it merges all all three of the priorities that you list. It is supposed to be a site for a boss battle, a miniboss battle, and then whatever else the GM throws in. It's so perfect for a crazed knight to weaponize traps and sightlines and weird corridors to just absolutely bombard [the players].

But it's also ruins. So, Tom, you have to have been thinking not just of “how is this going to be fun in the state that it is presently?” but “will this make sense as something that got destroyed?” Did you start with the unruined map first?

Tom Cartos: I did, yeah, I designed the full building unruined and made that work and then designed the ruined version in such a way that it was different from the intact version but also still made sense tactically.

Will Savino: It's so cool to see that in map form, because with the unruined version of this map, that's just what a castle would look like in a world before cannons, and then here's what the castle would look like with 100 years of disrepair and having the stones looted to build a separate village. But they both are super fun to play in!

Tom Cartos: I hope so!

Will Savino: Yeah, that was featured in one of your Into the Wilds books, I believe… Wait, was it? Was I correct in that? 

Tom Cartos: Thestwick Watch wasn't, because it's just too damn big. It's the biggest map set I've ever done still to this day, a full five levels. I've done smaller versions of a similar sort of thing because I enjoyed doing that map so much.

Will Savino: Well that's one thing I want to talk about is how you make stuff given that the eventual form factor is relevant to how you create.

Your Into the Wilds books, I think that they're just perfect because—and I'm not being paid by you to say any of this—but they're great, because one thing that we've learned with Borough Bound is it's really hard to make super big maps that are usable physically because table sizes are bounded! Like, real life tables can only be so big! But your books are perfect to just unfold and have for any encounter. Does that inform how you think about making maps, or are you just like, “eh, this one's gonna be too big for the book. Whatever.”

Tom Cartos: No, it definitely does. Even right from the beginning, my maps have always been sized in multiples of 8.5x11 so that you could tile them up and print them at home. And that has worked out very well for me as I've gone forward and decided actually I'm going to print these as well, because they are printable in standard sizes.

The Into the Wilds series I did on Patreon digitally for a long time. More so than I specifically planned it that way, I got the feedback from a lot of people using them that this is the perfect size for an encounter. When combat starts and you're rolling initiative, this is about how much space you need. My larger maps, I love them, but I think they are more useful for a dungeon experience, exploration, where you might have multiple encounters inside, and you might spend even multiple sessions inside them.

Those are a lot of fun, but they're actually potentially used less. You might only use one of those maps every couple of months in a campaign, whereas the encounter maps, when you want something quick on the fly, or something that's just a little bit more pre-planned, that size of 22x17 inches is perfect.

Will Savino: It's a problem we run into constantly. We made a magic school setting that is just thousands upon thousands of pixels wide, right? It is basically 12 encounter maps stitched together. And you could run an entire campaign literally on that map, which is great! 

But we also want to Kickstart that campaign setting, and literally how do you ever make a map that is that big? It’s too big to put on any table! Like, even one of those cool dedicated gaming tables. If you want to do an inch per square, I don't know how you do it. 

Tom Cartos: It's also potentially too big to put through a printer. You're limited by sizes of standardized commercial and industrial printers, which is something I'm finding. There's only so big we can go before you have to just chop it into pieces. 

Will Savino: And that’s what we’d do, of course. You know, we've talked to a few companies about basically making puzzle pieces that lock together. And that's cool, but it makes me so happy that most of my job is, “hey, take this mp3. Now you have an mp3.” Y’know, not having to think about any sort of physical media whatsoever.

Tom Cartos: It's been a fun challenge. Definitely. I’ve really enjoyed getting into physical products as a whole other side of the industry, and I've had to learn a lot, kind of figuring out as we go. I was fortunate that I set myself up well for it in advance a little bit, kind of by mistake more than by design. But even so, there's so much you have to figure out.

Will Savino: So, back on Thestwick Watch. I think that that map is great because it is simultaneously a realistic space, but it is also—even without additional GM notes—a good dungeon. Just shape- and size-wise, you could totally imagine a one-to-three-session arc where the players go in, have a bunch of weird encounters in each of the rooms, encounter a few puzzles, encounter some locked doors, and that's that.

Just talking purely about the map, are you thinking, “oh, this would be a good dungeon. I'm thinking about this from start to finish as a space to be explored in a dungeon format,” or are you just like, “no, this is a map, and if you want to treat it like a dungeon, that's your problem.”

Tom Cartos: No, I'm definitely designing it as a dungeon from the outset.

I consider it level design in the same way you would in a video game. It’s [about] having multiple options. I don't think there's much point in having a purely linear experience, even when everything's not literally in a straight line, because you want to give the players actual choice, not just the appearance of choice.

So I am considering, y’know, there are probably at least three ways in. There's the obvious way. There's the maybe also obvious but harder way. And then there's the sort of hidden secret way that they can find if they decide to take a bit more time and effort. 

I'm also considering how those spaces connect with one another. Also, the loop through the area, so, depending on how they enter each space, making sure they still reach the more important areas. And, along the way, there's a similar number of potential encounter rooms, so regardless of which entrance they take to get to the end, are there approximately five interesting rooms along the way?

Will Savino: Do you ever sketch out pathways? Like, draw an arrow through a space?

Tom Cartos: Yeah, absolutely. I'll draw one pathway [and then another], and make sure that they make sense. I also like to ensure that you can leave a dungeon a different way from the way you come in.

So kind of almost Skyrim-style, once you get to the end there's maybe a shortcut back to the start...

Will Savino: A one way door that only opens up once you defeated the boss monster.

Tom Cartos: Yeah, exactly, so you don't have to just narrate, “you go back through every room you've already been in but now everything's dead.”

Will Savino: It works perfectly. As a GM, there will be times where I need a map for some dungeon that I'm designing, and I'm annoying, so I never want to use anyone else's adventure design, dungeon design. I'm always doing that myself, but I'm very bad at designing my own maps, even MS Paint maps. So I love to grab someone's map and sort of retrofit my own dungeon philosophy onto it, and it's totally doable with your maps! Even ignoring anything that you've written, I can grab a jpg and just fill it out with my own ideas, and, again, that goes with [your philosophy of] more flexibility. You have the furnished versions of your maps, you have the unfurnished versions of your maps. GMs can read any notes that you've given them to build the dungeon the “Tom Cartos way,” or people can fill in the blanks themselves, and it will still work and look nice.

Tom Cartos: Great! I'm really glad to hear that because that's exactly what I aimed to do. 

Will Savino: Let me, let me give you the opportunity to plug your current Kickstarter. How many more days on that at time of talking?

Tom Cartos: There are two weeks. It finishes April 3.

Will Savino: I've been keeping mostly your fantasy maps in mind as we've been having this conversation, but this Kickstarter is all modern. You did not initially start releasing modern maps. That started a few years after you launched Tom Cartos, right?

Tom Cartos: Yeah, so I've been doing the fantasy stuff for about five-and-a-half years now, and TC Modern, I started… it'll be two years ago next month. So it's been a while now, but it is a more recent project.

Obviously, it ties in more to my architectural background, and it was also, like we were talking about earlier: always trying to do more but with less time. I freed up a little bit of time by bringing on another artist to help out with the fantasy stuff and rather than being like, “okay, I can work less now,” it was, “okay, what can I do with this extra time?”

It’s something I’d been thinking about that I felt would be fun and I decided to try as a little side thing, and it's done well! It's taken off, and now we're doing our first Kickstarter for it.

Will Savino: Do you have a sense of what systems people are using these modern maps with?

Tom Cartos: It is way more varied than fantasy. Like, obviously with the fantasy stuff, I can assume that probably 80% of people are either playing D&D or Pathfinder, and those are similar enough systems that I can just design around those systems to an extent.

With the modern stuff, I know people are using Delta Green, Shadowrun, Cyberpunk RED, Marvel Multiverse, Savage Worlds, Vampire the Masquerade, Call of Cthulhu. Honestly, dozens of others. Even board games like Zombicide and the Walking Dead games. They use the maps as custom expansions for them. 

Will Savino: I love that there's not even a consistent genre or theme for those games. It’s truly random!

Tom Cartos: No, absolutely. So I started out just having kind of purely modern-day stuff, but as I've found out how people are using them and what they want, I've leant more into a bit of cyberpunk, a bit of post-apocalyptic. I haven't gone all the way into sci-fi yet, but we'll see. Maybe down the line. I'm doing some more military stuff as well.

Will Savino: Just list some of the positives of these map books, because, every time I see them, I'm like, “oh right, they can also do that. That's useful.”

Tom Cartos: Sure, yeah. So, the, the modern one in particular, there are two different map books. Each one has 35 full-color spreads. The maps are 22x17 inches, like we were talking about earlier. It’s perfect for an encounter. And you get two variations of each one, so one is like a fully furnished version with all the props, really immersive. So if the GM just wants a location, you open up and it's ready to go, it's clear what everything is, and you can just play. And then you get a stripped down backdrop version, which is my simple variants where it's basically just the walls and the floors. The maps come with reusable vinyl static cling stickers of all the objects you find in the book, so you can place them down, customize it, they’re dry erase. So, it's perfect if the GM wants something ready to go or wants to prepare in advance

Will Savino: And the thing that I care about the most is, because it's spiral bound, it just lies flat.

Tom Cartos: That's right. Yeah.

Will Savino: It feels like such a stupid, obvious thing. “Wow 2025, and our books lie flat.” But it makes such a big difference! Because the concept of a map book simply does not work unless you can actually keep it open on the page that you want.

Tom Cartos: Yeah, yeah, exactly. 

Will Savino: Anyway, they’re great maps. I've seen the fantasy ones. I'm excited to see these in person. Any final plugs you want to give? 

Tom Cartos: Thanks. Yeah, check out my Patreon, check out my Kickstarter, I go to some of the larger conventions like UK Games Expo, PAX Unplugged, so come and find us there as well you can check out our maps in person.

Will Savino: Gen Con this year?

Tom Cartos: Not Gen Con this year. Unfortunately, my best friend’s getting married that weekend so I'm not gonna make it. 

Will Savino: “Unfortunately, my best friend’s getting married.”

Tom Cartos: Ha yeah, you can put that in. 

Will Savino: I certainly will. Alright, Tom, thanks so much!