inZOI: Director Reveals AI-Powered Realistic Simulation Secrets

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When people think of life simulation games, The Sims likely comes to mind, but inZOI is looking to shake up the genre with its AI-driven world, hyperrealistic environments, and an unprecedented level of player control. While it features some incredibly detailed visuals, inZOI is far more than “The Sims with better graphics.” In fact, based on what has been revealed about it so far, inZOI could probably be deemed the closest thing to a simulation of real life ever found in a video game.

In an interview with Game Rant, Producer and Director of inZOI and CEO of inZOI Studio, Hyungjun “Kjun” Kim, gave a thorough breakdown of inZOI‘s inspiration, design, and defining features. During the interview, Kim made clear his desire to offer players one of the most realistic and immersive life simulation games with inZOI, showcasing its uniqueness and quality in an increasingly crowded and beloved genre.

inZOI’s Inspiration and Defining Characteristics

Q: What inspired the creation of inZOI, and how did the initial concept evolve during development?

A: I’ve been a fan of playing simulation games with my son for a long time. In particular, we spent countless hours playing The Sims together. One day, my son asked why there weren’t more games like it. That’s when I realized there was a need for something new in this genre, and why I set out to develop inZOI.

However, in Korea, “life simulation” is still an unfamiliar genre, and there aren’t many references to draw from. This made the early development process quite challenging. “Life” is such a vast theme; it wasn’t easy to balance both depth and breadth in the game. The process of designing and developing the game systems was also a challenge.

Fortunately, my previous experience working on MMORPGs – where I created expansive maps and intricate item systems – proved invaluable. In MMORPGs, the main focus was to design and implement vast worlds. I was able to leverage that expertise to effectively build inZOI‘s open world. Moreover, as it is with life simulation games, an enormous degree of resources was required since we needed to implement various aspects of life. My experience in character customization, architecture, and housing systems from MMORPG development came in handy when overcoming this challenge.

To add, my background in building NPC systems, player relations and interactions in MMORPGs greatly inspired inZOI‘s NPC development and interaction systems. Though it is not an easy task, I continue to work hard to bring inZOI to life every day with my passion for the genre and my experience in developing MMORPGs hand in hand.

Q: What features do you believe set inZOI apart from other life simulation games?

The main advantages of inZOI come from its advanced graphics technology based on Unreal Engine 5 and its extensive community simulation system. This cutting-edge technology delivers high-quality, lifelike graphics that enable players to feel fully immersed in the game. To facilitate personalization, creative tools powered by AI, including a 3D Printer, Texture, and motion capture features, are included in the game.

In the city of inZOI, there are approximately 300 unique characters, referred to as “Zois,” who bring the urban landscape to life through their real-time interactions. The result is a dynamic and engaging gameplay experience due to the constant creation of different events and narratives.

inZOI aims to provide a platform where anyone can create their own unique story. To achieve this, we developed an extensive build mode and customization systems so that players can freely design everything from their surroundings to their characters. Additionally, we implemented various community elements – such as rumors, trends, and even diseases – to enrich storytelling. There is also an in-depth relationship system, a core aspect of narrative building.

With flexible creative tools in a realistic simulation environment, inZOI empowers players to easily build bring their desired lives to reality. This sets inZOI apart as a truly unique and innovative life simulation experience.

inZOI’s Approach to Creativity and Customization

Discuss the difficulties and advancements encountered when creating a comprehensive character customization feature like the one provided by inZOI, which allows users to modify aspects such as age, figure type, and clothing.

A: In inZOI, the character customization system was designed to give players an intuitive and flexible toolset for freely crafting Zois that reflect their individuality. One of the standout features is the “Facial Capture” system, which allows players to import their own likenesses into the game. Other various creative tools have also been implemented to support even more personalized customization.

The inZOI: Character Studio demo last August garnered a largely positive response from players. At the same time, we received a significant amount of feedback requesting more variety in body customization options. While enabling full flexibility in body adjustments would be ideal, this posed technical challenges. For example, excessive alterations to body proportions can lead to issues such as the disruption of interaction motions, or the character’s hands going through the body in certain positions.

Despite these challenges, we continue to make enhancements to allow for even greater variety in character customization. More importantly, thanks to player feedback, we have gained deeper insights into what players truly want. We remain committed to exploring the best possible solutions to refine the overall experience moving forward.

Question: By employing generative AI, inZOI designs game elements such as patterns and objects. How does this empower player creativity, and what technical challenges arose during its implementation?

A: inZOI goes beyond simple life simulation – it is designed to allow players to enjoy the game in creative ways. By incorporating various AI-powered creative tools such as the 3D Printer, AI-generated textures, and motion capture features, players can freely craft their unique characters and spaces.

By integrating AI, we hope to bridge the gap between players’ imagination and possible in-game realization. Traditionally, creating custom content in a game requires specialized technology or proficiency with different professional software. However, inZOI removes this barrier by providing on-device AI-based tools, making creation and customization much more accessible to everyone.

Of course, integrating AI into the game was not an easy feat. One of the biggest hurdles is optimization, which remains a key focus for ongoing development. In the current stage, AI tools perform best on high-end PCs, and other features require specific hardware specifications. Our top priority in future development is optimizing these AI tools to ensure a smooth experience for more players.

inZOI’s Aim for Immersion

Q: What strategy does inZOI employ to create a hyper-realistic game environment while still providing enjoyable, casual gaming experiences?

A: While inZOI is built around our realistic life simulation, providing a wide range of choices and a high degree of flexibility is equally important. Life simulation games appeal to a diverse player base, each with unique playstyles and preferences. To ensure a truly customizable and creative experience, we’ve integrated various options that allow players to shape their stories as desired.

For example, players can freely adjust the state of the city through the “Manage City” feature. This allows them to control various elements that influence the simulation to their desired level, such as city cleanliness, fire occurrence rates, public safety, population size, the number of vehicles, etc. Depending on how these factors are adjusted, the city’s environment can undergo either dramatic or subtle changes, giving players control over both the difficulty and overall setting of the game.

Players also have multiple ways to interact with core gameplay mechanics for enhanced flexibility. In the transportation system, while manual driving is an option, players can instead choose auto-drive or public transportation for a more streamlined experience. Ultimately, inZOI aims to maintain the immersive experience of a realistic life simulation, while ensuring that every player can enjoy the game at their own pace, in their own way.

To create realistic characters in the game “inZOI,” what specific AI technologies and strategies were used to make the non-player characters (NPCs) behave and interact realistically?

A: In inZOI, the city is brought to life by 300 autonomous characters, known as “Zois,” who interact with each other in real time, resulting in dynamic events and stories. This creates a more immersive and lifelike gameplay experience for players.

In particular, the CPC (Co-Playable Character) technology unveiled at CES 2025 further enhances the depth of the characters’ simulation. Unlike traditional NPCs, a CPC adapts flexibly to real-time situations, reacting dynamically to interactions aligning with the story of the game. Developed in collaboration with NVIDIA, this technology leverages an on-device Small Language Model (SLM) built with NVIDIA ACE. In inZOI, the technology enables “Smart Zoi” for more natural and believable character interactions.

When inZOI launches in Early Access on Steam on March 28, the Smart Zoi feature will be included on an experimental level. Unlike conventional rule-based NPCs, Smart Zoi is designed to deliver a more realistic simulation experience by making decisions organically and acting freely based on their surrounding environment and mental state. Additionally, players can carefully shape Smart Zois by inputting character traits through prompts, influencing and enabling their behaviors and actions aligned with those characteristics.

At the end of each in-game day, Smart Zois reflect on their experiences and summarize them in a journal format, which is used to inform their actions for the next day. These records, combined with their distinct personalities, create an evolving, individualized character arc for each Smart Zoi and a deeper, more engaging simulation experience for the player.

Since this feature, however, is still in its testing phase, it will not be fully complete at Early Access. Due to the computing demand of the language model, only players with compatible GPU specifications will have access to Smart Zoi. We will continue optimization efforts to bring the feature to more players to enjoy.

Question: What were the key technological aspects taken into account when designing the Facial Capture system in ZOI, a feature that lets players use their own images in the game, and how does this system boost player engagement and immersion?

A: The “Facial Capture” system in inZOI utilizes Unreal Engine’s “Live Link Face” application, a tool originally designed for MetaHuman animators and primarily used by developers. However, since inZOI is built with Unreal Engine, we saw an opportunity to make this technology accessible to players. By combining this “Facial Capture” system with inZOI‘s highly realistic graphics, players can bring their own faces into the game, enabling a new level of creative content creation. We were especially thrilled to see creators using inZOI as a Vtuber streaming tool, demonstrating that this feature enhances not only immersion, but also creative applications.

Currently, this function is only available on iOS devices. We plan to continue research and development of more tools beyond facial capture to support player content creation and storytelling, further expanding platform capability.

inZOi’s Gameplay and Open World

Q: Can you elaborate on the active careers feature and how it enhances the day-to-day life simulation for players?

A: Careers or jobs in inZOI serve as a primary source of income, providing the resources necessary for sustaining life. Players can choose from a variety of professions available in each city, experiencing career progression or demotion based on their performance and work hours.

As a player in this game, I’m constantly juggling my time between earning a living and maintaining my personal liberties, much like we do in reality. I need to invest time into nurturing relationships and enhancing my abilities, just as one would in real life.

The more a Zoi commits to their job, the less time they have to interact with others. Naturally, the Zoi will deepen relations with work colleagues while also honing their job-related skills. On the other hand, prioritizing free time over work allows for broader social interactions and diverse skill development, enabling flexible gameplay.

In essence, the harmony between professional responsibilities and personal time is essential in shaping Zoi’s adventure, enabling players to fashion their individual gameplay approach that seamlessly combines an authentic simulation feel with a great deal of liberty.

How was the process of designing the varied environments in Dowon, Bliss Bay, and Kucingku carried out by the team, and were there any real-life locations that served as their inspiration?

A: Though the open world environment of inZOI was initially designed to perfectly mirror real-world cities, we reduced its scale and adjusted the structure to better suit the simulation gameplay. Dowon draws inspiration from “Gangnam” in South Korea, capturing its sleek urban landscape and bustling lifestyle. Bliss Bay reflects the relaxed and vibrant coastal charm of Santa Monica in the U.S., recreating its romantic atmosphere. Kucingku is based on a specific region in Southeast Asia, incorporating tropical landscapes and rich cultural elements.

We’ve made a number of adjustments to ensure that each location preserves its unique vibe and lifestyle, while still integrating seamlessly into the game’s shared systems. As a result, players can explore cities that feel both familiar and fresh, experiencing the thrill of traveling through a newly reimagined world.

Inquiry: How is the intricate weather mechanism implemented within the game inZOI, and how does it influence both gameplay and character actions, ultimately shaping the player’s overall experience?

A: inZOI‘s dynamic weather system is designed to randomly generate daily weather patterns based on each city’s real-world climate. For example, in the coastal city of Bliss Bay, snow never falls, while in Dowon, temperatures can drop low enough for snow. As the weather changes, the Zoi will feel cold or hot and react in realistic ways by changing their outfit or carrying an umbrella outside.

These weather elements go beyond just visuals to affect overall gameplay mechanics. When the player adjusts the weather via “Manage City,” the cityscape changes dynamically – the Zoi will wear different clothes and accessories and decide whether to use an umbrella. If the Zoi refuses to dress appropriately for the weather, they may suffer illnesses or even life-threatening conditions, adding a more realistic survival element for the player. This elevates the depth of inZOI as it impacts the Zoi’s daily life and choices in an ever-changing environment, creating a rich and immersive simulation experience.

Q: Players can extensively customize furniture and interiors. What tools and options are available for this, and how does it contribute to the game’s creative freedom?

A: In inZOI, furniture and interior customization go beyond simply changing colors and materials. Players can design, create, and even invent new items using a variety of tools and options.

For starters, our “Custom Furniture” feature allows players to assemble pieces from multiple parts, giving them full control over its shape. For example, when creating a table, players can select and combine legs, tabletops, and decorative elements, resulting in unique and diverse designs.

On top of this, we integrated AI tools to further enhance player imagination. The 3D Printer tool converts user-input images into in-game objects, creating items with completely new shapes and textures. In addition, players can generate images from user-input text, which can then be used as designs or pattern elements.

This customization system not only enhances interior design, but also allows players to place their personally crafted furniture and decor in the game to reflect their own individual style.

Players can exhibit and share their creations using “Canvas,” an in-game feature where they can post and download custom designs such as furniture, clothing, houses, etc. We’re eager to see how players will customize their unique spaces within the game inZOI.

A: What does the structure of the game’s economy look like, and what mechanisms exist to facilitate substantial player advancement throughout the gameplay experience?

A: inZOI‘s economy system is designed to provide maximum freedom, while ensuring that the player’s choices are not overly restricted. Traditional jobs offer stable income, and players can also earn money through other means such as freelancing or even extreme actions like theft. However, the game does not make realistic labor excessively difficult, as the goal is to let players place their own meaning to money within the life simulation.

In inZOI, we handle money with care. We strive to find a middle ground, blending realism with unencumbered creativity in gameplay.

Additionally, inZOI includes a progression system where players can gradually develop “Skills” over time through various activities and interactions. Enhanced “Skills” unlock new opportunities such as additional activities, purchasing new items, or selling self-made creations for extra profit. This structure allows players to experience meaningful growth, while enjoying a gameplay style that suits their preferences.

How do rules control and influence interactions between characters and character relationships within a game, and what effect do these dynamics have on the gaming experience?

A: The characters (i.e., Zois) living in inZOI‘s cities interact in real-time based on their unique attributes such as personality traits, values, preferences, and skills. This full community simulation allows for the natural occurrence of various events – including rumors, trends, and illnesses – influencing social interactions and relationships. As these events unfold and create a ripple effect, they shape a dynamic, unpredictable narrative and ensure that each playthrough offers new storylines and evolving relationships for a richer simulation experience.

A key feature in Early Access is the “Event System.” This allows players to plan and schedule events at specific locations, inviting other Zois to social events such as parties or weddings. With this system, players can form relationships in even more diverse ways, craft their own personal stories, and experience more realistic gameplay as events that occur in the game are systematically connected. We’ve also added more realistic life and relationship experiences, including crime, dating, and visitation, designed to be as complex and diverse as things are in real life.

Q: inZOI includes drivable cars and other transportation modes. How do these features integrate into daily life simulation, and what was the development process like?

A: Transportation is one of the core elements that contribute to a realistic life simulation experience in inZOI. The development team wanted to reflect real-life movement patterns, where people walk short distances and use cars or public transportation for longer trips. However, implementing vehicles in the game was a big decision. Not only was it challenging to implement realistic traffic signals and road systems into the game, but there was also uncertainty about whether players would actually want to drive themselves. As such, we reached out to our Discord community for feedback and ultimately decided to include both manual and automatic driving options.

In the Early Access version, the traffic and driving systems have not been fully developed, which may lead to some limitations. However, players will still be able to buy cars, drive around the city, and even give rides to friends for a realistic driving experience. We also made sure to have different public transportation systems in each city, with subways in Dowon, and buses in Bliss Bay serving as the main modes of transportation. Recognizing that not everyone may want to solely focus on driving, inZOI offers multiple transportation options – walking, public transit, or using the auto-drive mode to get around easily. By balancing immersion and convenience, we’ve made inZOI‘s daily simulation a richer and more flexible experience.

Q: What are your plans for post-launch support? Can players expect regular updates, expansions, or new features based on community input?

A: More details about inZOI‘s post-launch plans will be revealed at the upcoming Early Access Online Showcase on March 19. One thing we can say for sure is that we are committed to continue evolving the game even after Early Access by actively listening to community feedback. Our goal has always been to create a game where anyone can be a creator and tell their own story. However, it has been a rough process since there weren’t many existing references for the genre or its development, so we had to experiment and research on our own.

Despite the challenges, we decided to go into Early Access to bring inZOI to players as soon as possible, allowing us to refine and enhance the game based on real player feedback. While there will certainly be areas for improvement, we are dedicated to elevating the game’s quality step by step, driven by our passion and drive for the game. As much as players are eagerly awaiting inZOI, we will continue to make an effort to meet and exceed expectations.

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2025-03-17 01:39