4 AM Skywatching at Sardinia: Art and Aerology in shaping FSEnhancer

By: Peter Tram
February 14, 2019

The skies drown in silence, it’s four in the morning. Enrico wakes up and enjoys the natural air conditioning from the cold wind blowing from the north before sunshine. The island, being almost uninhabited, gives him some much-needed peace from the hustle and bustle in Rome. Situated in the middle of the Mediterranean, his summer home in Sardinia proved a perfect spot to bask in the natural wild landscapes and pristine water. Enrico quietly prepares for another strenuous day out; summer holiday is a prime time for his daily sky watching.

Art and Aerology:

All of Enrico’s samples are taken in the summer in Sardinia. He sets out to his usual spot next to the ocean, sets the camera on a tripod with a wide angle lens, then pointed it towards the sky and sets the camera to take a photo every 3 minutes during sunrise and every 15 minutes in the later morning. With each stage in a day, Enrico shoots three areas of the sky; in front, the side and opposite of the sun. Additionally, notes were taken on his handy laptop for each observation he has made on the clouds. The routine is done again in reverse for sunset and then it’s rinse-and-repeat for the next day. Such routine was done a few random times for each weather condition just to make sure to capture every detail, even if X-Plane uses only one of the two. “I made more than just a single set to simulate the daily variations in light conditions. Mist, smog, relative humidity, temperature are all factors that influence the sky colour on a daily basis”.

The accumulation of photographic data from these trips enable Enrico to better understand how the gradients in the sky and clouds look at each stage in a day, it’s what also brings FSEnhancer closer to photorealism:

Left: Real-Life | Right: X-Plane 11


“AUG 16, 2018
Portrait of a sunrise
My work on gradients has almost finished.
These are the samples I used to build a new set of skycolors called "Boreal"”

Time for Textures:

Enrico plops down on his work desk and begins the process to appropriate the images into textures; starting with importing the images to Photoshop, each image natively in RAW to preserve most of the tonal and dynamic range. The first step is to generate sky textures: slowly and meticulously, Enrico merges the front, side, and opposite shots into a single texture. Each stage of a day representing a single “bar” in the X-Plane sky texture, the process repeats for each bar:

Stemming way back to the first FSEnhancer, the process remains largely the same, but it was a faster and more simplified process in comparison to the upcoming version 0.6. There were few samples for every texture; just the one perpendicularly oriented from the sun was used to create the perfect average sky colour, but that means it would essentially look the same in every direction. It’s a different story for 0.6, Enrico never tried to build a set of textures entirely from his camera and with such a huge amount of samples, but he is ready to bring more variety using a library spanning over a thousand images.

Clouds in 0.6:

Clouds are perhaps the biggest improvement of all, for the process of producing the textures has completely changed. In particular, the procedure where clouds are “extracted” out of the image went from a semi-automated process of desaturation and contrast adjustments to a meticulous removal process of each wisp of condensed vapour:

Same same, but different:

In the current (and older) versions of FSEnhancer, Enrico used to greyscale the cloud image, and adjust the background to be as black as possible with contrast and curves trying not to influence the cloud, the black regions would then simply be masked into transparency; this gives a respectable degree of transparency variation- but it’s nowhere near the level he wishes for a payware product.

For clouds in 0.6, the process is much more tedious; Enrico manually selects the clouds and deletes the background/sky area. The hardest and most time-consuming part of the process is providing varied transparency; clouds in real life are not uniformly transparent, there are thinner and thicker areas. For such areas, transparency is manually drawn and erased carefully. Every cloud sub-texture (with 16 clouds in every texture) requires at least a few hours of work:

Preview of newly extracted cloud textures, subject to alpha channel refinement and tonal adjustments.

“It's all about details” Enrico affirmed. “That's what makes the difference and change the game in my opinion.” Enrico wishes to not stop at simply texture edits, he wants to venture into more customisation with coding in the future. “I must say it, I define myself a perfectionist with a kinda limited developing knowledge and an obsession for too complex things.”

Complete Overhaul:

FSEnhancer’s development doesn't end with textures however, scripts were given a major overhaul, particularly in the haze department; 0.5 provides the necessary base to developer further upon for TrueHaze, TrueWaves and so forth. The photos also proved to be instrumental in guiding the refinement of the Lua scrips. In version 0.6, haze rendering has been updated to fit 11.30+, some datarefs have been deleted, and a lot of new ones have been added.

Enrico spent a good amount of work on the direct/ambient light levels for every weather condition, which is controlled by a few datarefs that influence the general lighting feeling of the scene - the effects being most visible in cockpit view:

Enrico is one of the few who attempts to bring a fully photographic approach to producing weather visuals, each release a step up in the development process. From the atmosphere to the clouds: for 0.6, the graphics are all completely sourced from his photo surveyance of the sky. Enrico elaborated that these processes are just the tip of the icebergs, a quiet session sitting at his spot while note taking on his observations were one of the most crucial component in his research.

To pay or not to pay?

When asked why he is so willing to go through such a lengthy monotonous approach, Enrico remarked “It's the fact I'm a geology student I guess, I can't help myself from putting a touch of science everywhere. I think a bit of science knowledge is needed when you provide realistic sky textures for a flight sim.” For Enrico, the combination of meteorology and photography are essential to the ultimate weather add-on. The massive effort behind the sky and cloud textures is partly the reason why he also considers 0.6 to be the first version worthy of being Payware. “Considering the amount of time and efforts I spent during the last months to make FSE look as good as possible, the days spent in collecting photographic data and Photoshop editing, I honestly think FSE v0.6 is very likely to become a payware product.”

"I want it to be light on your wallet"

Enrico promised that it will be priced at a rate where its accessible to as many users as possible “It will be cheap by the way, extremely cheap."

So the promise made here is simple...light on the wallet, heavy on the features! The effort undertaken by Enrico so the sense of immersion is achieved must be applauded and supported. Long may we continue to have talented developers supporting our hobby and enhancing our experience.

Best of luck, Enrico!

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