This Caving Sim Uses Sounds & Textures Captured in Real Caves

Have a look at Cave Expedition, an upcoming caving simulator from Moonmilk Games. The game was recently revealed on Steam and has received 25,000 wishlists in one week. 

The sim focuses on realism and offers players the chance to experience dry and wet caving as they descend into enclosed squeezes, large chambers, and uncharted depths. Players will take on the role of speleologists with professional gear and equipment, such as helmets, headlamps, climbing ropes, shovels, and more, and navigate eerie underground cave systems. You can embark on an adventure solo or with friends in a co-op mode supporting up to 4 players. The perilous expedition will demand teamwork, planning, and communication.

Moonmilk Games is a Sweden-based studio focused on making the game experience as authentic as possible. The team behind the project includes real-life cavers, who captured sounds and textures during actual expeditions in caves around the world. Alongside their caving experience, the developers bring a strong background in game development, with particular expertise in rendering technology and hardware optimization.

Martin Calander, Producer and Co-Founder of the studio with a caving experience of 10 years, told 80 Level that the idea for the game appeared during his second cave diving course in Sardinia. Martin's instructor was scanning a cave using photogrammetry. After learning that Martin was a game developer, the instructor suggested they could turn the scans into a game, and Martin's response was immediate: "Are we gonna make a game?"

The first prototype of Cave Expedition was a smaller-scope VR project focused on cave building, relying on photogrammetry scans as scenery. Development became a year-and-a-half journey with multiple iterations before the project evolved into something bigger, pursuing an ambitious goal: a caving sim that captured the full experience with as much realism as possible.

"For me, the game brings together three things I love: caving, game development, and difficult technical problems," shares Martin Calander.

The gameplay is heavily inspired by real-life experience and highlights aspects of caving that you can only learn in the field, many of which may not be obvious to people without cave-diving experience.

"Most people think squeezing through tight spaces is what makes it extreme. That's certainly part of it, but moving through a cave also involves physical effort, planning, equipment, and technical skills that are much less familiar. I want those parts of caving to come through in the game too."

The initial idea of using the photogrammetry scans directly as scenery was changed to developing a custom pipeline that turns the scans into 3D textures, which can be blended together in the engine. Calander even built his own photogrammetry rig with a ring flash, ensuring a more even lighting and avoiding harsh shadows that usually appear when taking photos inside caves.

Learn more about how the game's textures are created in a series of videos:

The eerie, immersive atmosphere of real caves is supported by sound recorded in real places using binaural microphones worn directly in the ears, which helps recreate what cave divers actually hear. So, what can you hear underground? The sounds of unexplored passages, flowing water, and, of course, the gear itself – ropes, carabiners, and descenders.

So far, the team has captured textures from caves in Sweden, Norway, and Romania, with more locations planned for future expeditions.

Cave Expedition is planned for release on Steam, PlayStation, Nintendo Switch, and Xbox in 2027.