MT84 help please

[ahuimanu 50]

Hello,MT84, near Kalispell, Montana is up on a plateau which is nearly 1000 feet taller than the surrounding valley. I've read a few threads here, but a definitive answer on how this problem may be easily fixed is not clear to me.I am using FSGenesis 38m mesh for the area.Thanks,J-

[ahuimanu 50]

Hello,Okay, perhaps a picture will help describe my problem as I had several views but no advice for the fix:http://kailua.isy.vcu.edu/images/mt84_s.pngThanks,J-

[Guest Hugo]

Hum! That looked as an easy one! OK, In Fs with original mesh, MT84 shows as in Img 1 below. So nothing to do with your 38M meshes. So the first I tryed was to put the cabalistic flatten formula in the Addon Scenery entry of scenery.cfg, that more or less follows the yellow path in Img 2 at an altitude of 3100' the general height of the surrounding area. [Area.038]Title=Addon SceneryLocal=Addon SceneryLayer=38Active=TRUERequired=FALSERemote=Flatten.0=3100,N48 13.69,W114 23.03,N48 13.69,W114 22.04,N48 12.77,W114 22.04,N48 12.77,W114 23.03Now Mt84 looks like shown in Img 3 but the the runway still hangs a thousand feet above!! No problemo, Afcad will take care of this. So using Afcad and selecting the Aiport Properties, I modified the elevation to 3100'. I did the same to the Runway and Start Location entries and saved the result. Afcad then places a new airport data file as AF2_MT84.bgl under ...Addon SceneryScenery folder. We should now be in business!Restarting FS and going to MT84 shure seams to work as shown in Img 5. But, Yikes!, as I roll to the runway base, I get proped up to 4000', the former runway elebation, in less than a blink time!!Hum! What am I missing here?Hugo.

[ahuimanu 50]

Hello Hugo,I really appreciate the time you've taken out for a step-by-step approach to a fix. I believe you are running into the reason for my original question: there does not seem to be a simple and straight-forward approach to fixing these things. I will apply your fixes to get me to your same state, but it appears we both need some additional advice in how to fix this problem.Thank you.Anyone able to help us?J-

[Guest Hugo]

Hi J-Is it a coincidence? F. Dienstbach has uploaded today at Flightsim.com a mod file that does exactly, and succeeded ;-), what you are after, mt84fix.zip.It modifies the runway base and make it a gravel one with a very much stretched center line. I did a search on Google for infos on the exact nature of MT84 and only found this link http://www.placenames.com/us/p806458/ but not much there and Google Earth has not enough resolution over this area to show it clearly :-).Yet, I wonder what I missed with my proposed approach!!Anyone?Hugo2nd edit: According to NFD the airport altitude would be 4000' *:-*http://worldaerodata.com/wad.cgi?id=12417.4*AH

[Guest Hugo]

Bump!Hugo

[ahuimanu 50]

>Bump!>>HugoHey Hugo,Been away for a few days. Wow, I'll have a look at that fix right away. I wonder why these are such vexing problems?J-

[LuisFelizTirado 33]

Hello John,Where is this place, anyway? Forgive my ignorance - this is probably the gateway to some fabulous natural landmark like the Grand Canyon or Yosemite, isn't it?The problem is due to conflicting sources of altitude information in Flight Simulator.First, there is the altitude mesh. This forms a basis on which to construct terrain. Don't forget that mesh resolution varies in the game. For the area of Mower Field, the default mesh is a LOD 6; that is over 6oo meters between data points! Not very detailed and will certainly not show the correct relief. The closest high-resolution mesh is the LOD 8 default mesh for Waterton-Glacier Park.Then, there is the airport altitude. This is defined on the one hand by the AP file containing runways, taxiways, aprons, and approaches, etc. This file contains a "reference altitude" for these elements that places the visual parts (runways, etc.) at this altitude and also affects the user aircraft and the AI aircraft.Along with that AP file, there is a FL file that flattens the surrounding area to the reference altitude. Why? Because FS does not yet support sloping runways, so to avoid them diving into the ground, it is leveled flat. The AP reference altitude and the FL altitude are usually the same.So, if all these altitudes agree at the area of the airport, then you will not see problems like the one in your picture. If, however, either the mesh or the AP reference altitude disagree, and by a lot, then you get either a plateau for the airport or a chasm where the runway and taxiways sink into the terrain.Solutions:1. Probably the easiest thing to do is to get a better (higher-resolution) mesh for the area. Is that Justin's mesh that you are using? Generally, he knows very well what he is doing, but it could be that his source data was flawed in that area. Perhaps there is a problem with it there, so you might want to make your own. A better mesh will raise the base altitude of the terrain to the level of the airport, so you will not see such dramatic cut-offs.2. You could otherwise modify the AP reference altitude so that it coincides with the default mesh. This is not the best solution, first because the FS Team gets their airport data from Jepp and while it is not perfect, it is pretty close to reality. So you would be getting less "as real as it gets" if you lower the airport. But, also because changing the airport reference altitude is not as easy as changing it in AFCAD. AFCAD DOES NOT change airport reference altitudes. Please see this thread for more information:http://forums.avsim.net/dcboard.php?az=sho...ing_type=searchAlso, you would have to change the flatten information, either by creating a new flatten or modifying the default file, if you change the AP reference altitude. 3. Finally, you could raise the surrounding terrain using "flattens". This is a pretty delicate undertaking and rarely looks very good.By the way, best wishes to all the forum members. May we all still be making scenery when the next New Year comes around.Best regards.Luis

[ahuimanu 50]

Hi Luis,Thank you for your reply. Mower field, near Kalispell, Montana, is a gateway to Glacier National Park. Not only was this the coolest area modeled in Train Simulator, it was also an area I had the privilege of traveling through by Amtrak train myself in the 1990s - beautiful.I am using Justin's mesh and it is accurate. What is not accurate is the elevation of Mower field. You are right, my attempts to make a change with AFCAD2 did not do much. Hugo provided a flatten solution here, but it doesn't change the runway information, so it is a partial solution. I've also asked at in the scenerydesign.org forum and have received some interesting information there too. I'll never use or land at Mower field, but it ruins the look and feel of that valley near Kalispell and is actually a slight hazard when on approach to runway 2 at KFCA (wow, now KGPI). So, I can live with a partial solution. However, if parts of the runway are suspended 800 ft above the runway, then it is still a flight hazard.Visually, the flatten approach works, but it seems that changes need to be made in at least two places to fix this.Best,J-

[rhumbaflappy 113]

Hi J-Have a look at this thread:http://forums.avsim.net/dcboard.php?az=sho...24653&mode=fullDick