Mountain fog line

RTV

New member
Hi there,

I'm running P3D v4.5 with Active Sky 16 v7410. I'm wondering if someone could tell me which setting needs to be adjusted in Active Sky to eliminate the band of fog in this image. It's a problem I've seen often in mountainous terrain. I initially thought it was a problem with the P3D rendering engine, but when I accidentally started the sim without Active Sky running tonight, I noticed the problem was gone. A bit of testing quickly revealed that this is definitely being generated by Active Sky as the screenshots below will demonstrate.

First, this is what I'm trying to fix:

With AS.png

Here are the weather conditions that generated the image:

METAR.png

This is the Fair Weather theme that was running before I noticed AS wasn't on:

Default Fair Weather.png

After confirming that Active Sky generates the layer by enabling and disabling it a couple of times, I decided to see if it was a problem with P3D's fog generation
in general. I did so by loading the Building Storms and Cold Fronts themes, which both generate fog and haze. The results:


Default Cold Fronts theme.pngDefault Building Storms.png

In both images, the stark demarcation at the top of the fog layer is not present, so you don't get the banding effect. I have no interest in flying in default weather themes. But by the same token, I really hate the banded fog layers, and if there is a way to get rid of them I'd love to hear it. For what it's worth, I tried fiddling with all the visibility settings and cloud options while the simulator was paused. Though some of them had an effect on the scene, none of them fixed the problem. I don't run any shader software like PTA. I do have REX Sky Force 3D, but I noticed this problem long before that was installed, so I don't think it's playing a role.

One last AS picture from a different angle. The issue is really prominent in this one:

With AS 2.png

Thanks in advance for any suggestions!
 
Last edited:

RTV

New member
OK, I've done more tinkering and have some observations. If you want to check the situation presented in the last image of my initial post yourself, the sim date and time are August 5, 2020, 3:34 UTC. Only the Active Sky engine is enabled in historical mode with time locked to the sim. Coordinates and heading are in the image.

The problem seems to be related to Active Sky's handling of visibility. Increasing minimum surface visibility in increments gradually reduced the band of fog until it disappeared entirely. I assume it was just pushed away from the aircraft beyond the point it could be seen against the mountains.

Maximum upper visibility also affects it. Matching it to max surface visibility (75) clouded out all of the distant mountains entirely. Increasing to 99 had very little effect. But pushing it one more SM higher immediately reintroduced the haze band and dramatically increased the view distance. It was like a switch being thrown - you can turn the band on and off like a toggle between 99 and 100. When toggling back and forth, the effects on visibility seem to dramatically exceed 1 SM. I see mountain tops which are far beyond the nearby ones appear and disappear along with any distant clouds.

Altitude makes a difference. With maximum upper visibility at the 199 default, 7500 feet looks pretty bad as one can plainly see above. At 10000, the effect is still present but not nearly as objectionable. At 15000 feet, it's basically a non-issue (at least for me - others may disagree). But at all these altitudes, I still get the "flicking a switch" effect when changing max upper visibility from 100 SM to 99 SM. The decrease or increase in visibility is dramatically greater than 1 SM. I notice another similarly dramatic transition between 149 and 150 SM with the plane at a higher altitude. Everything between 101 and 149 produces no difference, but the sky suddenly becomes clearer at 150. Increasing back to the 199 default produces no discernible effect.

In thinking about it, I've noticed that Active Sky's portrayal of visibility at lower altitudes has often left me feeling like I'm flying in a perpetual cone of fog, and the toggling effect I noted above suggests there may be something wrong with the visibility component. Is there a setting in Active Sky or Lockheed Martin that needs to be adjusted to fix this?
 
Last edited:

maxam

Super Moderator
Hello,

Great analysis! Active Sky does indeed add haze or fog based on season, temps etc. I have found that using ASCA and/or ENVTEX does soften the appearance as well as with the settings as you have described changes the visuals within the sim. There is no "one size fits all" but we do our best to provide tools with which users can make adjustments to the appearance of weather.

I think your post will help others with similar issues.

Thank you for posting!
 

RTV

New member
It's no problem - thanks for providing a great addon for P3D. No other weather engine I've tried compares to Active Sky.

I was thinking about a solution to this problem as I flew at dusk tonight. Conditions were clear and the the ugly horizon visibility band was in full evidence. Distant clouds were chopped off at the base and mountaintops were poking through the horizontal line where the visibility transition occurs. Frustrated, I manually changed surface visibility to 199 SM. This eliminated both problems, and the horizon in general looked nice from 3000 feet AGL. The only thing lost was a bit of haze at the base of the mountains, which is a small price to pay for getting rid of the banded horizon effect. But of course, I was then stuck with those unchanging weather variables. This isn't really a great solution.

The visibility depiction (specifically surface visibility) is responsible for these visual anomalies. The issue is most apparent in higher visibility conditions and can be mitigated by manually setting surface visibility to a much higher value. Active Sky can't change the way P3D depicts visibility, but it is obviously capable of adjusting visibility on the fly. If it could be configured to automatically adjust surface visibility to a much higher value when it exceeds a certain METAR-reported level, the visual anomalies should be mostly eliminated. A slider could be provided to allow users to set the activation value to their liking. As for what to override the surface visibility level to, I'd suggest the user's maximum upper visibility setting would be the best choice. This would allow users to cap maximum visibility if they so desired.

The default activation value could be 200 SM, which effectively turns the feature off. Users would move the slider lower if they want to use it. The disclaimer that this may result in an inaccurate depiction of real world conditions that is attached to a couple of the other sliders could be included. To give an example, if I set this value at 15 SM, Active Sky would provide its normal depiction of visibility whenever METAR-reported surface visibility is 15 SM or less. But if I subsequently flew into an area where METAR-reported surface visibility exceeded 15 SM, Active Sky would override that value, replacing it with my 199 SM upper level visibility value. If I then flew back into an area with lower visibility, it would return to the default presentation.

What do you think? I'd really like to see something like this added, as it would provide a workaround for the distracting visual anomalies without having to alt-tab out of the simulator or sacrifice the variable weather and transitions from higher visibility to low visibility conditions that make Active Sky so great.
 

maxam

Super Moderator
Hello,

Thank you for the feedback, interesting idea. The dev's will have to look your suggestion and hopefully come up with something after seeing whether this is feasible.
 

RTV

New member
Thanks for considering it, Robert. Best wishes. Oh, and I should mention that all of my flying is done on P3Dv4.5 with the last hotfixes applied. I don't know if LM changed the way visibility is handled in v5. If not, this workaround would probably work for the new version as well.
 
Last edited:
Top