VRChat Aviation: The potential of the Open World Movement Logic System
Updated: May 3
In a place where I could be wandering magical forests or dancing in clubs, I'm looking forward to being a passenger on a regional flight.
Distance is one of the most well-known limitations in VRChat aviation (VRCA). Whether it's player vs. player air combat or general aviation flights around a familiar airport, everything takes place within a generally agreed upon maximum distance that has been in place since VRCA began. Flying long distances to new locations in lands far from home is integral to aviation's identity and function. Being unable to take extended flights seemed to be an accepted restriction by the VRCA community, but as of June 2022, the tools for cross-country flights are now publicly accessible.
Why is there a limitation in the first place? It is because of the inherent floating point precision errors in the Unity game engine, which world creators in VRChat use to create flight worlds. VRChat has a default world size limitation of 20km x 20km, which works perfectly fine for what this VR social platform is made to do. For chatting with friends in a virtual pub, playing mini-golf, or touring scenic vistas, that's plenty of space. But when flying aircraft the limit is apparent within just a minute or two.
Sacc Flight, the primary VRChat flight script, can provide a 40km x 40km distance increase, making aviation more plausible, but the problem remains. The farther towards the edge of the recommended distance you travel, the worse the floating point errors get. In aircraft, it can get to a point where instruments become illegible, and eventually, the vehicles themselves become uncontrollable.
Here is a short, easy-to-understand video example of this error as seen in VRChat:
The quick fix that flight focused creators use is called "Repeating World Distance." A basic explanation provided by VTail64, VRCA world creator and photographer, summarizes:
"The way it works is there is basically a box boundary. Within that box is the play area, and how big this box is, is based on that variable. When a plane reaches one of these "walls," where the X or Y value in the gameworld reaches that distance, aka "hitting the wall," it forces that coordinate to become negative. So if you reached X:20000, Y:97, your next location would be X:-20000, Y:97."
From the player's point of view, they are instantly teleported across the map from where they hit play area's border. This keeps players within a predetermined area, ensuring they won't fly so far away from the world's center the user experience becomes unplayable. While this is a sound choice to protect the user’s experience, the distance limitation remains a firm barrier.
Despite the 40km x 40km limitation, some aviation-focused world creators continue to create aircraft systems and refine existing systems. Because each creator has their goals for developing aircraft, not every system seen in one VRCA world will be available in all the others. These systems include multi-frequency radios, AWACS/GCI style radar, onboard aircraft air-to-air radar, aircraft ground radar, trim control, functional glass cockpits, working analog gauges, heads-up displays - all equipment you’d expect to see in Microsoft Flight Simulator or Digital Combat Simulator World.
Most releveant for the subject of this article are aerial refueling, TACAN, and horizontal situation indicators (HSI). These are essential long distance flights in civilian and military aircraft. Even when cross-country flights were not possible, creators developed these systems anyway, purely out of their love of aviation.
The introduction of the Open World Movement Logic (OWML) system by ZhakmiZhako, has now unlocked the ability to fly hundreds of kilometers at a time. The OWML system is a floating origin point shifting system that, after users travel across a specific distance away from the center of the world, moves the terrain according to the coordinates that the users have traveled. The users are then teleported to the center of the world space, avoiding further floating point precision errors. See our interview with the developer for more information.
Before the public release of OWML on June 26th, 2022, a test flight of the system was performed on March 23rd, 2022. The system's developer, Skyward Flight Media staff, and members of the largest VRCA community, the Black Aces, flew a record setting flight in the now public OWML demonstrator world. Utilizing YC-1000B aerial refuelers and SF-1 jet fighters, they flew non-stop for three hours and ten minutes over 1826km. With TACAN and HSI to guide them as they flew over multiple airports and air-to-air refueling to keep the short-ranged SF-1s aloft, the OWML system was stress tested with positive results.
[Collapsible List] March 2022 OWML Endurance Flight Test Information
x06 SF-1 by Sacchan
x03 YC-1000B by SA-77 Silpheed
Pilots, Support Staff
Cubeboy (SF-1 Pilot)
KOSM0S1 (YC100B Pilot)
Razor (SF-1 Pilot)
Ribbon-Blue (SF-1 Pilot)
Riko (YC100B Pilot)
Sliick Back (SF-1 Pilot)
TheHighdolMaster (SF-1 Backseater)
Uni Power (SF-1 Pilot)
Longest Recorded SF-1 Flight
Ribbon-Blue (Pilot), TheHighdolMaster (Backseat)
Longest Recorded YC100B Flight
KOSM0S1 (Pilot, Tanker Alpha)
Riko (Bravo, Tanker Bravo)
A muted and time compressed video of the flight is available for video evidence.
As of the time this article has been published, there are few public examples of large-scale worlds using OWML, but they are in development. The most recent addition is a still in development project released by Yumemidori on September 7th, 2022. This 2000km squared map presents an early iteration of beyond visual range combat. Aircraft on both teams presented in the map have short range infrared missiles, semi-active radar guides and active radar guided air-to-air missiles with an engagement range of up to 100km.
In my opinion, creators that focus on combat aviation will most likely need a longer time to develop for the OWML system, depending on the type of weapon systems they are trying to simulate. Long-range weapons require specific aircraft systems to deploy them. General aviation focused creators seem to have a majority of the systems they need for long range communication and navigation already working, theoretically lessening the amount of time they would need to incorporate OWML into their projects.
VRChat aviation is effectively freed from one of its most significant limitations, so long as world creators take the time to learn and implement Open World Movement Logic system. Vacation-style trips to exotic locations are now possible. Regional flights with multiple passengers seem as though they are on the horizon. Long-range combat sorties are feasible and already working in limited cases. If anyone knows where I can pre-register for the first VRChat airliner flight, DM me!
About the Writer
Aaron "Ribbon-Blue" Mendoza
Co-founder of Skyward Flight Media. After founding Electrosphere.info, the first English Ace Combat database, he has been involved in creating flight game-related websites, communities, and events since 2005. He explores past and present flight games and simulators with his extensive collection of game consoles and computers. Read Staff Profile.