A new weather engine awaits us in Microsoft Flight Simulator 2020, developed by Asobo Studio in partnership with Microsoft. We’ve been promised a number of important things for the new program in relation to weather and these include a new atmospheric engine, new special weather effect, a new night engine, volumetric clouds and live real-world weather.
The developers have started from scratch and built a revolutionary weather engine for the simulation. Asobo have said they really wanted the lighting of the world to be as realistic as possible and to take advantage of all the new advances and techniques from the video gaming industry. Visuals for simulations are produced by scattering – the distribution of light and other phenomenon to produce a visual picture. The new scattering systems unifies all the differing sources of light, sunlight, moonlight, starlight, city-light to create super realistic effects.
Other factors affecting the scattering are atmospheric humidity and pollution. To a pilot, these factors affect visibility and as such need factoring into the simulator weather system. The simulator atmosphere is layered with variable particle densities to produce this.
Shadows also play a key role in the realism of simulator weather. The weather engine scatters all the light photons from the different light sources through the layers and as a result shadows have been massively improved when compared to previous simulators. Mountains cast shadows on the clouds, clouds cast shadows on themselves and the mountains, and all the different layers of clouds cast shadows on the ground. This gives a general feeling of realism that has never been seen before.
Realistic volumetric 3D rain has also been modelled and I have to say is one of my favourite features. Firstly rainbows. Volumetric rainbow scattering ensures that rainbows form exactly when, where and how they would in real-life, and this is also affected by the humidity, viewing angle and rain. These parameters are manipulated in the rain scattering calculation resulting in super realistic rainbows – even the secondary/echo rainbows are visible in the right conditions! The rain droplet impact on the cockpit windshield is also modelled. Each drop is affected by a combination off of speed, thrust of the engine and precipitation level. The rain scattering calculation stretches each drop of water on the windshield, giving an ultra-realistic effect.
Two other weather phenomena simulated are fog and icing, both important considerations to real-world pilots and subsequently important to virtual pilots. 3D volumetric scattered fog is generated in the same way as low-level cloud and can vary in density and consistency. Icing formation and intensity depends on the same real-life parameters and context as it would in the Earth’s atmosphere. Ice propagates on all the surfaces including wings, tail and windshield. All de-icing systems are simulated correctly for the virtual pilot to correctly apply the appropriate actions in these circumstances.
A new day and night capability has been developed, along with a full yearly cycle. This means the position of the Sun will be correct at any given time. The same is true for the accurate positioning of the Moon and stars. A clever video on the Discovery Series shows what scrolling through time of day and date does to the weather and positioning of the above features.
At night, ground based lights such as city, road and runway lights have been programmed to illuminate the clouds, any fog and even any aeroplanes flying over. Such levels of realism mean Asobo Studio developers believe night time VFR (flying solely by visual reference) flying is possible.
Water reflections have also been modelled. As well as man-made lights and other obvious factors like the Sun and Moon, light levels alter the characteristics of bodies of water. This is particularly noticeable when comparing a dull dark day with a light sunny day – see image below.
Undoubtedly the star of the flight simulator weather show are the new volumetric clouds. Lots of importance has been placed over the years on the look and ‘feel’ of clouds in flight simulators and we feel quite rightly so.
The clouds are ultra-detailed. There are 32 layers to the cloud modelling from sea level up to high levels. Each layer has its own density, shape and as Asobo describe it – ‘fuzziness’. The clouds can be viewed from any angle (they’re completely 3D) and all cloud types are supported by the simulator. The life of the cloud affected is also affected by wind. Up-draughts and upper level winds affect both the formation and dissolution of the weather system. The clouds are simulated all-round the globe. Viewing distance is set at 600km, which is massive, but really important when flying airliners as you can see much further from the flightdeck windows. The developers have also said the view inside the clouds changes as the density evolves/varies as you fly through.
Microsoft Flight Simulator will have a pre-set weather function, ranging from clear day to broken cloudy day to stormy weather and rain. However, everything so far has been designed so the software can receive accurate data for real-world, real-time weather. By injecting this data directly into the simulator weather engine, a representation as close as possible of what is actually occurring is possible. There are 60 layers of worldwide real time weather data used to create the real-world environment and in addition to the cloud data elements mentioned earlier, 20 other items of weather data are simulated, including: pressure, humidity, temperature, windspeed, wind direction and wind gusts. All these inputs mean you would notice and see all the phases of a front passing through your actual location in the simulator itself. Having wind data also allows modelling of jetstreams. This is fantastic news for the virtual airline captain and realistic world navigation can be planned as it is in the real-world. This level of real-time accuracy mean virtual pilots can make use of other meteorological data sources and be able to correlate the charting to the simulator conditions.
In summary, Microsoft Flight Simulator 2020 will have 3 main weather highlights – full spectrum weather seamless flying in real-time, volumetric skies and live real-world weather data. This is an exciting time to be a Virtual Airline Captain.