From console to VR: MudRunner’s journey to virtual reality

Initially, the task looked simple: make a port of MudRunner for Quest headsets.

Despite MudRunner VR being our first game for Meta Quest, our team includes VR-industry veterans and those who worked on the original MudRunner port to mobile. While making a VR game wouldn't be too much trouble, we realized that a simple port wouldn’t be enough. From a technical standpoint, Oculus was easy to work with; their guidelines are simple and made the optimization process less of a challenge. For MudRunner VR, we realized vehicle controls needed to be honed for seated play, especially for wired headsets, because wires get snagged often while playing standing up. Standalone headsets like Oculus simplify this issue and the optimization process.

Additionally, instead of chasing the quality of models and then downgrading the graphics, we deliberately started with low parameters of models and gradually improved the graphics so we can focus on the free resources of devices. While this imposed its own limitations on the maximum quality of graphics, it allowed us to speed up the development process and determine the list of effects and mechanics involved.

VR can be tricky and accessibility was important for us. We focused heavily on accessibility, designing our game to be comfortably played while seated, with controls optimized for using just one controller while also overcoming motion sickness. We studied various issues like difficulty walking, impaired vision, dysfunction of one of the arms and weak vestibular apparatus. Coincidentally, it just so happened that during development our lead game designer tore a ligament in his foot and a tester broke his arm, so they spent a lot of time with the game making sure it worked well for them. As this was the first VR project for our testing team, some of them experienced motion sickness while playing the game initially and it helped us make the overall experience smoother, and ultimately better for players. We were familiar with many problems being solved firsthand!

We also focused on seated gameplay, which allowed for more accessibility to players with walking difficulties and tackled the topic of reduced motion sickness. We quickly realized during the research that driving while standing would quickly cause dizziness and disorientation. In the interface design, we also followed guidelines intended to increase the comfort of the game for players with vision problems. We used large fonts, contrasting pointers, bright and prominent outlines, and object outlines that stand out from their surroundings.

We designed MudRunner VR in such a way that you could play the entire game using only one hand by mirroring the controls for both controllers. We did face an initial problem because the throttle and brake were separated on the triggers of different controllers. Eventually we made it possible to control the car with only the stick, which turned out to be of great help to those who get tired quickly from holding the controller on the weight and in the outstretched hand all the time.

Throughout development, MudRunner VR became our Ship of Theseus. We tried to make changes to the game code that were necessary. As a result, the game and assets were rewritten by 99%. At first, we thought we had everything ready and just needed to optimize the existing assets for VR, but realized that the shortcomings of the models, which looked beautiful in third-person view, were more striking than ever in VR. As a result, everything was redesigned from scratch. In the original game, car interiors were purely decorative, but for MudRunner VR, we made them fully functional with a diegetic interface and interactive elements. Using photogrammetry to digitize real-life prototypes of our vehicles wasn't enough; real life comfort felt claustrophobic in VR. We redesigned the cabins for virtual ergonomics, adjusting lever lengths for players for ease while seated.

While in the process of playtests, we realized that our locations were too lifeless. For example, the technical limitations of the device did not allow us to simulate wind through the movement of leaves on trees. This caused a sense of liminal spaces, which contrasted with the philosophy of our game. We had to animate the world in other ways. Now, something is constantly happening in the game - there are mosquitoes swarming near bodies of water, birds circling somewhere in the distance, wind driving dust and some papers along the roads. These things are not very conspicuous but reduce the discomfort from the feeling of disbelief in the liveliness of the surrounding world.

For those new to the Runner series, we made sure to include basic story elements to get them up to speed.  As they get experience, the game gives them a chance to drive vehicles they likely have never driven before. Then, moving beyond that we had to look at how the original MudRunner had a lot of gameplay conventions that would look out of place in VR. How is refueling handled? How are repairs performed? Why do all these actions happen automatically? That's when the main idea came to us - the player should be able to get out of the car.

For the first time in the series, players have the ability to exit the car, and this isn't just a decorative feature - a number of gameplay tasks and mechanics are built around it. We adhered to the principle - all game mechanics should be immersive. Why do we have to stay inside all the time? If we're already out of the car, why limit ourselves to the winch? We wanted the winch attachment process to be as intuitive as possible. The winch "pulled" us out of the cozy cabins. Why don't we also refuel manually? If we've already started interacting with the environment outside the car, why limit ourselves to just the refueling gun?

We also had to revisit the movement system. The game engine did not provide for the possibility of getting out of the car. Consequently, it did not provide for such things as navmesh. Fortunately, the philosophy of the game doesn’t include NPCs, so we avoided the difficulties of working out their models and animations, but we had to adapt the movement to the existing physical model. The main problem we had with movement was the cars themselves. Usually, if there is an object for interaction in a VR game, its location is supported by the level design, so the player has no difficulties with interaction. With us, however, most of these objects are located outside of cars. This means that the interaction object may be located at an uncomfortable height or angle and access may be blocked. We had to invent fine-tuning systems tied to dynamic areas for teleportation, so that the player wouldn't accidentally end up in a soft-lock situation. These areas could overlap so we had to invent a complex prioritization system. Even this is not a panacea, so in some situations the player may have to drive a little further away.

While we want to make the gameplay as realistic as possible, it’s difficult to balance that realism with fun. We tried to achieve more interactivity and immersiveness than other similar VR titles. We wanted to show that game vehicles are big and complex mechanisms, and our protagonist is cool because he knows how to handle them. At the same time, we were looking for compromises with ease of mastering and ease of control. The player should not feel frustration while driving these iron monsters. Sounds, vibrations, visual effects and dashboard indicators all work to convey the feeling of real driving. We made working side mirrors, introduced interaction with the map, repair mechanics and coupling inside the game tablet. Even the key is not initially inserted into the ignition socket. All of this is to give players more reasons to have deeper interactions with the entire game environment. We made it a point to put all important game information on the dashboard. Now, to turn on the headlights you don't need to go to a special menu anymore; simply reach out your hand and press the button. We devoted a lot of effort developing the cabins to captivate new players and encourage exploration!

We just launched the first big update, incorporating feedback from players. Things we hadn’t originally thought about were brought up as players spent time with the game. We want to address any QOL elements provided they can be worked in. So, things like allowing the driver’s side window to be opened for improved rear visibility and adjustable crouching speed. We added more fuel canisters and diversified vegetation, including more dry trees in swamp biomes. We introduced a 2D arcade machine to our game hub, which is a fully-fledged game made in the style of classic machines. We’re also working on integrating Free Locomotion mode, adding handles, ladders and mounts to help with climbing and fueling.

We love the fact that the franchise is constantly evolving and appreciate players providing feedback. Experiments like Expeditions and MudRunner VR are necessary for the series itself and the modern gaming industry as a whole. Saber is constantly on the lookout for new ideas and our team is very proud to be able to contribute. We put our love for the original into MudRunner VR and are pleased to see players are enjoying the game so far!