An important plugin has been released for flight simmers that use on-line weather in X-Plane. It's important because X-plane has a basic primary flaw: it sets infinite visibility from the "9999" visibility tag, which causes frame rate drop - because the very distant scenery is rendered - and is unrealistic. This plugin fix it. The METAR "9999" tag means visibility 10km or above.

 

You can download the plugin here:

 

http://forums.x-plane.org/index.php?app=downloads&showfile=19748

 

Create a folder "PythonScripts" inside "resources\plugins" folder and put the file "PI_VisibilityLimit.py" there.

 

The plugin is a Python script, so you must install Python. For 64-bit X-Plane Windows, install "Python 2.7.5 Windows X86-64 Installer". Get it here:

 

http://www.python.org/download/

 

Then download "PythonInterface.zip" (the 2.7 version)  from here:

 

http://xpluginsdk.org/python_interface_latest_downloads.htm

 

Extract this file and put the folder "PythonInterface" inside the "resources\plugins" folder.

 

Start x-plane and check if the plugin is running (look on the "Plugins" menu, "Python interface").

 

And some guys complain about the limited visibility in altitude :-)  Now, there is a plugin to limit it even more ;-)

 

But, jokes aside, it makes sense, for surface visibility, although any limit imposed artificially when visibility set to 9999 in the METAR is always subjective because it might be 11km, 50km, etc...  

 

The same problem applies to cloud bases. If above your sector alt and not of Cb type they will not be reported, even if you have a OVC of stratocumulus...

I think the "not so high" visibility at high altitude problem is something related to XP graphic engine.

 

Regarding the plugin: it relaxes the limit as altitude increases, and it does consider the dew point, etc, and the good thing is that the script is an open text file (as the LUA scripts), so you can edit it and modify the behavior... :rolleyes:

 

Actually I was about to write my own plugin to carry out such task, but this one was released first.

 

 

and it does consider the dew point

 

Ah! That is indeed good to know, as well as the "ralaxation" with alt!  I will certainly try it ;-)

I like it - seems to have a much more convincing haze effect than default.

 

However it keeps changing my weather setting from real weather to set weather uniformly for globe. Is that intended?

How much of a performance gain do you notice, if any?

I like it - seems to have a much more convincing haze effect than default.

 

However it keeps changing my weather setting from real weather to set weather uniformly for globe. Is that intended?

 

I also noticed this after installing the plugin. I have to go into weather settings after flight has loaded to set real-weather, and redo that every time i for instance swap airports etc.

 

Feels like quite a nice fps improvement too, not sure. Haven't noticed any visual difference yet thou (flew only in real weather with normal cloudy weather)

I've noticed that i have to manually put the sim on "grab real weather from the net" mode and then click on "download right now" button if I want to refresh the weather (i.e download current weather) after some flying time. Yes, this is annoying. I´m going to write a note on the first post. Update: I can´t edit it. No edit button!

I also noticed this after installing the plugin. I have to go into weather settings after flight has loaded to set real-weather, and redo that every time i for instance swap airports etc.

 

Actually not much so far, but there's some FPS gain :smile: indeed . You have to consider my PC hardware spec that is not "low-end".

 

Some tests:

 

SCSE 211700Z 31008KT 9999 FEW025 12/02 Q1020

Plugin off: 32 FPS (20SM)

Plugin on: 35 FPS (11.2SM)

 

MDPC 211800Z 09013KT 9999 SCT023 31/24 Q1018

Plugin off: 34 FPS (20SM)

Plugin on: 37 FPS (11.2SM)

 

No FPS gain on CAVOK:

ETNG 211750Z 06007KT CAVOK 31/16 Q1018

Plugin off: 34 FPS (20SM)

Plugin on: 34 FPS (11.2SM)

 

How much of a performance gain do you notice, if any?

 

 

SCSE 211700Z 31008KT 9999 FEW025 12/02 Q1020
Plugin off: 32 FPS (20SM)
Plugin on: 35 FPS (11.2SM)

 

Honestly then, I'll pass, not because of the FPS but rather because of the fact that for such a wide range between T and Td I see no justification for "just" 11.2 SM horizontal visibility...

jcomm,

 

This is the plugin logic (from the PY text file):

 
HIGH_MAX_VIS = 50000.0          # meters at high altitude (float)
NORMAL_MAX_VIS = 30000.0        # meters in normal conditions (float)
MEDIUM_DPRATIO_VIS = 21000.0    # meters when difference between temp and dp is less than 10
LOW_DPRATIO_VIS = 18000.0       # meters when difference between temp and dp is less than 5

def FlightLoopCallback(self, elapsedMe, elapsedSim, counter, refcon):

        visibility = XPLMGetDataf(self.VisibilityDataRef)

        maxVis = HIGH_MAX_VIS

        diff = XPLMGetDatai(self.TemperatureSL) - XPLMGetDatai(self.DewPointSL)

        elev = XPLMGetDatad(self.elevation) / 0.3

        if (elev < 8000):

            if (diff < 5):

                maxVis = LOW_DPRATIO_VIS

            elif (diff < 10):

                maxVis = MEDIUM_DPRATIO_VIS

        if (visibility > maxVis):

            XPLMSetDataf(self.VisibilityDataRef, maxVis)

        # Return 1.0 to indicate that we want to be called again in 1 second.

        return 1.0

You can have good ideas...

Now I see the plugin considers the elevation as well

yep, the idea itself is good! 

Jcomm, the logic and code of the plugin is very very simple. You could download it and then change the values of just HIGH_MAX_VIS, NORMAL_MAX_VIS, MEDIUM_DPRATIO_VIS, LOW_DPRATIO_VIS, to tune its behaviour.

Yes Murmur and Emerson, I agree, it's easy to edit ant tune to one's preferences.

 

The original idea is an excellent one too. It makes me think that other interesting "weather interventions" could be made through dataref access...  I confess I didn't even know the Td made part of the internal variables, since it is not listed in the Weather menus...

If one of you guys could tweak the logic to make it more realistic...