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TBM 900 Release Week Day 4: Rain Effects & Release in Hours!


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In just less than 7 hours from the time I write this the TBM will be released (Midnight EST)!

Today we are going to discuss rain effects, and as usual more can be seen in action on today's final livestream happening at 6:30pm EST (2230 Zulu).

You can watch the livestream by clicking here! (Previously Recorded)

Now, let's talk about precipitation!

Although we often wish for it, not every flying day is sunny. Whether it's just a light shower, or a full blown thunderstorm, we have paid particular attention to make sure your simming experience will always be an immersive one. To that end, we have taken the "let's make it physically accurate" approach to rain simulation.



So how does it work? The entire explanation is several thousand lines of C and OpenGL shader code long, but in short, it works roughly like this:

1) The rain simulation gets precipitation intensity from X-Plane
2) Based on the intensity it randomly generates where drops on the windshield have fallen (taking into account a host of factors such as window slant)
3) We computes forces on every portion of the windshield, such as acceleration, propeller thrust and wind velocity
4) We move the water around on the windshield, allow for things such as droplets to merge, evaporate and just roll around
5) Based on the depth of water at each point, we refract the light coming at you from the outside world, giving the illusion of looking through water droplets

And the best part: it's all done on the GPU. GPUs are unbelievably scalable computational systems and can do this kind of simulation with relative ease.

So we can get amazing behavior, such as the droplets being blown away by propeller blast with very little FPS cost (although the exact FPS impact will depend on the speed of your GPU):

But be careful when flying in heavy precipitation. While on approach, the propeller blast and the aircraft's motion through the air breaks most of the droplets apart and helps clear the windshield:

But slow down with little propeller thrust and the windshield can become absolutely innundated if the downpour is strong enough:


And why we were simulating water flow, why not incorporate windshield temperature into the calculation as well and display ice as well?


To deice the windshield in this case, in the TBM you have a choice of two systems (which can even be combined for maximum effect). There is the good old electrical heater. Powerful, but draws a lot of power, so the manufacturer has limited it to a small portion of the windshield:

Or you can try to use hot bleed air used to heat the cabin. Simply redirect it to the windshield defrost vents and watch the ice melt away. But as you can imagine, both of these systems have their capacity limits. So don't expect to always have a clear windshield as if nothing was happening outside. We've set up the simulation to be as realistic as possible training a heathy respect for the weather and learning the limitations of the aircraft.

We'll see you in the livestream linked at the top of this page, and more importantly, for the release that's only hours away!

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