Runway lights visible through fog and clouds


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Hi,

Runway lights are implemented with billboards and an emissive materials, with their emission_visibility_distance = 30000m (by default). While this is great with a clear sky, it breaks all realism with ground fog or when flying over a dense cloud layer. The lightpoints simply shine through unobstructed (like if they are rendered after the cloud).

At the moment, a quick and dirty fix I implemented is just to reduce their emission_visibility_distance when flying inside or above the cloud. But it would be great if the incoming 2.14 could tackle this issue (or 2.14.0.1 if already too close).

Thanks!

 

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Hi Stephane,

Billboards are not only used for the lights emulation, but in other cases as well, so there are some hard-coded logic is being hidden inside the shader for that.

For example, opaque billboards currently should be correctly attenuated by clouds, but not with the haze (ground fog). Alpha blend billboards  on the other hand are not handled by clouds, but should work fine with haze.

Can you show us your billboard setup (node and all the material options) so we can try to reproduce the same behavior on our side?

Thanks!

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Posted (edited)

Hi Silent, you can have a look at the AH_VDB_F_G vdb you made for us, and look at the indicator_light_lod_0 billboards. They have additive blend mode, with Emission enabled:

Spoiler

image.png.b36399e11c04a1998c3d766f706366d1.pngimage.png.637b50bfc4efc1e11ba356d15c07d34b.png

They look great in day/night time, but they do poorly within or above clouds (also, note the water is displayed over the clouds, wrong transparent order I guess):

Spoiler

image.png.fbfff04f23d1e6e3accb90ceb57263e5.pngimage.png.0d3afb2d5318b3781e394e615a30c5c3.pngimage.png.69eb46264c2669aae1a95489158cbf05.png

At the moment I worked around it by controlling the billboard's material Emission/Visibility Distance parameter. But this is just a poor workaround. Mainly because it cannot simulate the real visibility in the following case:

image-3.png?w=1400&h=9999

Here, the airfield must be clearly visible when flying above the cloud layer because the cloud layer is "thin" vertically, but the airfield must be invisible when flying through the layer, because then the fog thickness is "thicker".

Usually, the pilots are used to talk about the RVR (runway visual range) and this is the value we must input in CIGI atmosphere/weather ctrl.

https://www.boldmethod.com/learn-to-fly/weather/how-runway-visual-range-rvr-works/

This is clearly critical for our next operations.

I know 2.13 can't do this, but I really hope 2.14 (or next) will be.

Also, the current Haze simulation is good for long range (a few km to tens of km), but fails for short range.

I would have made more test with 2.14beta but the current beta visibility implementation is not suitable (as reported in the other 2.14b post), so I'll look more deeply in the next 2.14 occurrence (beta2 or release?)

Thanks!

 

 

Edited by Amerio.Stephane
(typo)
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I forgot that you are using clouds for the ground fog. That makes things a bit difficult.

That situation should be better with 2.14 release with new clouds sorting options:

https://developer.unigine.com/forum/uploads/monthly_2021_04/image.png.69eb46264c2669aae1a95489158cbf05.png

In your case you can also additionally add some environment haze on the far distances to cover the distant billboards.

Sorting clouds with water currently the hardest part and this behavior will remain the same in 2.14.x releases.

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