Image courtesy of Spaceflower

Let Them Trade is a relaxing strategy game made using Unreal Engine 5

80 Level

Spaceflower is an indie game development studio founded back in 2019 by Game Designer Thomas Otto, located in Nuremberg, Germany. In just three years since its inception, the company has grown into a team of six developers. They are united in a passion for creating artistic and innovative games, developed a free-to-play project Viewergames Arcade, a small racing game made specifically for Twitch streamers, and published NeoBird’s 2D puzzle-platformer World Splitter.

Right now, the Spaceflower team is working on Let Them Tradea peaceful and relaxing economic simulation strategy inspired by real-life board games and set to release next year. The game features a hexagonal grid, AI-controlled traders, and an immersive game world that tasks you to overcome various obstacles, ranging from wild rivers to greedy bandits, in order to build a network of prosperous and flourishing towns. With Let Them Trade being Spaceflower’s opportunity to realize a more extensive project, the team required a powerful solution that would satisfy both artistic and coding needs and help them streamline the development process, and thus, the team chose Unreal Engine 5.

To learn more about the production process behind the upcoming strategy game, we spoke with developers from Spaceflower to ask them about Let Them Trade’s gameplay and features, its main mechanics, and find out how the team utilizes Unreal Engine to simplify and accelerate development workflow.

How did you get started with Let Them Trade?

Art/Game Design Lead and CEO Thomas Otto:
It all started with a board game Thomas made back in 2015. After Spaceflower was founded in 2019, there was the need for a first debut project, and the idea came up to make a video game inspired by a board game. This laid the foundation for Let Them Trade. Initially planned as a straightforward, more casual game, it quickly evolved and got more features and mechanics that turned a simple concept into a rather complex economy sim with many things to do and take care of.

Could you tell us about the game’s main mechanics?

Thomas Otto:
The player's main task is to build cities, with each producing certain goods and resources that others need either as consumables or to process different goods, forming production chains. The AI-powered traders in the game world then independently look for a good deal and go off doing their trading. Players only control things indirectly by setting taxes, subsidies, and such, and do not set specific trade routes; traders decide those for themselves.
Image courtesy of Spaceflower

Besides the traders, there will be other independent inhabitants. For example, bandits that try to rob traders, knights who protect traders and cities, and others. These mechanics tie into the idea of only the indirect influence of the player. For example, if the player wants to take care of the bandits, they would need to put a bounty on those bandits. Then, hopefully, a knight nearby gets interested in collecting that bounty and goes to deal with the bandits. The idea is to present a lively world with all the inhabitants running around and doing their thing.

The game will also feature quests–some of which tell little stories–and in-world events, like a carnival coming into a city or a city being run over by a plague. There will also be many unlockables, like building types you unlock while progressing in the game, and more permanent unlocks–perks, notable buildings, or even decorations for the room surrounding the table you’re playing on. The unlocks happen via progress, fulfilling certain conditions, or via the research tree, where the player needs to actively perform research by investing player budget and world resources. Additionally, thanks to the extensive mod support the game will feature, the community will be able to keep adding new things to discover or build, new challenges, or even new game modes.
Image courtesy of Spaceflower
How and when did you decide to choose Unreal Engine for the project?

Lead Programmer Michael Hengstmann:
The first “proof of gameplay” (way before it became a prototype) was made in Unity simply because the team had a lot of experience with it. We heard more and more positive things about Unreal Engine, and since Michael already had a solid background in C++ and Unreal Engine, we agreed to try it.

Initially, we had some concerns, as UE is not well-known for strategy games. Therefore, we set a timeframe to determine which engine we want to go with. Quite early, we realized that Unreal Engine would not only work out fine for Let Them Trade but also has great advantages compared to others. You can tell that the engine developers themselves use it for game development. A significant advantage is that Unreal offers many integrated tools and that we don’t have to use too many third-party assets. This allows us to focus more on the actual game development rather than tooling. Lastly, having access to the entire engine source code is a big plus for us and has helped us to implement many unique mechanics.

The engine’s tools and features have already saved us more time than the conversion and familiarization with it cost us.

What’s your take on Unreal Engine 5’s latest updates?

Michael Hengstmann:
Upon trying UE5 for the first time, the artists instantly fell in love with Lumen and Nanite. Not only do the new features enable us to set up fantastic visuals, but as mentioned above, they allow us to focus on the actual artistic work. On the coding side, there are very useful features like One File per Actor for better management of version control or the Wavefunction Collapse algorithm for map generation. As for the latest updates, each update brings enhancements and even new features, so once the notification “Update Available” pops up, we update and enjoy not having to worry about everything breaking, as it sometimes tends to happen in other engines. Now and then, we take a peek into the near future by checking out the latest version of the engine source and building it to try it out and see what’s coming.
Why did you decide to choose the strategy genre?

Thomas Otto:
We did not plan to make a game of this scale and strategic depth from the beginning. Let Them Trade was intended to be a small, minimalistic trading game. However, we had many ideas we wanted to implement in the game, so the game’s scope has grown a lot over time. It might be a risk or a challenge to unite all the elements and mechanics. It's always a balancing act between clarity, complexity, accessibility, and depth of play. And, in the end, the numbers in the economic system must work out smoothly. Finally, the result needs to be fun and not repetitive, even after long hours. We are not afraid of it but have great respect for the task.

How does Let Them Trade’s main game board work?

Michael Hengstmann:
Each hexagonal tile is a separate actor on the main game board with several components that take care of the game tile’s functionalities. When you build something on a tile, we have a particular component that knows what meshes to add and to set visible or invisible, so each game tile can react to what’s happening.
Image courtesy of Spaceflower
Each tile actor also triggers global events for “on hover” or “on clicked” for all the other mechanics, like the build mode for building things on tiles or the city UI when an existing city has been selected, to act on the user input, show details in the UI or manipulate the tile accordingly.

Depending on what you are building, a special component is added to the tile actor to add the functionality of that building to the tile–the whole game board is quite component-based. Several components control the general behaviors of the tiles, and special ones add other behaviors or functionality. The game tile actors are spawned in the playfield based on a simple definition of “what kind of tile goes where.” Mostly, there is a three-dimensional hex-coordinate system used to address and find the tiles. Sometimes, it is translated into 2D coordinates.
Image courtesy of Spaceflower
Did you use any procedural systems when creating the board to streamline the production?

Michael Hengstmann:
We have a few different systems that accelerate our development. One of them is the hexagonal map, which is defined by a simple JSON file. This allows us to build maps very fast or generate them procedurally. We already have a web-based map editor, which a community member created. We also save a lot of time and budget by making all our subsystems and core mechanics fully dynamic and modular.

For example, the game tiles are all registered at runtime, which means to add a new game tile, all we need to do is to fill out the structure with the definitions, have an actor representing the base tile, and one call to “register game tile” and you got a new tile, ready to be used. This gives us maximum flexibility while saving a lot of time for adding new things and aids in keeping the game accessible for mods and community assets.

Regarding the visual side, as Unreal Engine takes care of all the fancy lighting via Lumen and LODs via Nanite, we can focus on just the models, textures, and animations. Due to the tabletop wood figure style, we have simple, hard-surface meshes animated without complicated rigs, mostly directly in Unreal.
Image courtesy of Spaceflower
How did you approach the game’s economy and balance it to make the Let Them Trade challenging yet not frustrating?

Thomas Otto:
Since we want to have a game that allows the player to determine their own pace, we want the possibility to automate processes as soon as they become repetitive while always allowing players to control or indirectly influence processes at the right spots.

The player builds the cities with houses and production facilities. The system starts up independently. Cities sell and buy goods, whereby traders automatically start distributing the goods. The player’s job is to observe, modify, balance, and optimize so everyone in the game world gets their needs satisfied.

We want to prevent the frustration of instant losing conditions, so if something goes wrong, the game sets the player back a bit, and they get the chance to rebuild in a more optimized way. Furthermore, time-critical goals are only implemented sporadically and are well-considered to support the relaxing aspect of the game. However, completing the castle, which is the soft goal of the game, will be challenging. For this, a well-functioning economic system is needed. Since we know how complex the final balancing will be, we have made all relevant mechanics and values very flexible and easily accessible. We will conduct a lot of playtests publicly and internally, and because of this, we will probably have to change and adapt a lot, but our flexible system design will significantly reduce our effort in doing so.
Image courtesy of Spaceflower
What is your current roadmap, and where can people follow the game’s development process?

Thomas Otto:
Currently, we are still in a relatively early stage of development. We have learned a lot after our first gamescom presentation and are currently overhauling the cities and traders. We’re also missing more prominent features like multiplayer and event systems, and there is a lot of UI and UX work left to be done. So, we still have a lot of exciting things ahead of us.

If you want to follow what we are doing and maybe even test it, you can come to our Discord and follow us on Twitter. We are also very active on TikTok (in German).

We also want to say a huge thanks to the FFF-Bayern, a reliable funding partner for the film and games industry in Bavaria.

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