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scott967

Help from experts pzl..step by step on flattens

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HI all. Need some help from folks more versed in scenery than I am. One of my favorite airports is KMRY. I have installed FSGenesis 38m mesh in that region and the airport sits on a plateau and looks...er..silly. I have browsed everywhere and learned that either the scenery or the AFCAD is wrong. But I don't know how to flatten things. There are two AFCADs for the airport--the stock gives it's altitude as 254' and an addon I added also gives its altitude at 254'. FAA charts list 254' and AOPA database lists 257' It seems then that the airport is at the right elev. If you slew to the side of the airport the elevation is 171'. The plateau is thus about 75' feet high.Is the proper thing to do here to change the data in the AFCAD to 171? Will that affect appearance? I'd like to keep the airport at its real elevation if possible. Or does one bring the ground up to meet the airport? If so, how? Using a flatten? How do I make one and where do I stick the line in the scenery.cfg? KMRY is just off shore of the Pacific ocean. If I raise the elevation of the surrounding area, what happens where the land meets the shore?I would love some step by step help, as I am confused. Sorry I know so little about this but that is why I came to you experts!

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This is a classic case illuminating the "flat airport" limitation of MSFS.Go to www.airnav.com and plug in KMRY. Note the runway threshold elevations:10R - 155 feet28L - 257 feet10L - 197 feet28R - 256 feetBoth runways are not flat. 10R is over 100 feet lower than 28L. Opposite ends of the same runway. FS can only depict a perfectly flat runway. Flattening the airport artificially will leave a plateau at one end and a canyon on the other. And vice versa. Take your pick. Either one is likely to be barely acceptable. Danged if you do, danged if you don't.Not really much that can be done about it until FS has the ability to depict uneven airports and runways.-------Justinhttp://www.fsgenesis.netHigh Quality Scenery for FS200x

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I see what you mean, and the problem in my opinion it is the installed mesh that gives a wrong elevation figure (171 feet) around and under your airport. This has the effect that the airport seems to be placed on a plateau. Sometimes the meshes are wrong the other way and the airport then will sit in a "gorge".I have no idea how to adjust the mesh, but hopefully someone else in this forum may steer you in the right direction.A custom drawn "flatten polygone" set to 254 feet and covering the "valleys" outside the airport boundaries might help, but I have not tried it myself.Such a flatten can be easily constructed in e.g. "Architect" and most likely also in the "Airport" freeware scenery design program.BestBjorn

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Thanks guys. Justin: I understand that FS cannot reproduce sloped runways or airports with runways at more than one elevation. Indeed, the AFCADs give the same (and a single) elevation for all runways. The area underpinning the airport is perfectly flat (I can live with that). But as soon as one leaves the tarmac or a runway there is a slope. In other words, the airport is raised relief. The question is how to lower the table top that is the airport to match the surrounding area or raise the surrounding area to be even with the table top.Can others help?

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Try this, under "How to use the flattening switch"http://www.microsoft.com/games/flightsimul...neryobjects.aspYou'll also have to do quite an extensive amount of editing by decompiling the applicable BGL, editing the source code, and recompiling. Unfortunately FS2004 doesn't have the ability to simply "exclude" flatten polygons. You may successfully flatten the terrain without a big headache, but then your airport and all the objects will remain floating, or you'll have an invisible deck. It can be a real PITA, and in the end, you still have an unrealistically perfectly-flat airport at a different elevation.Bjorn, the problem is that the terrain, though accurate under the airport, is not a constant 171 feet. One elevation point might be 171 feet, and in real life that 38m square at the real airport is 171 feet, but there are hundreds of other elevation points there that aren't 171 feet, just as there are hundreds of other areas there in real life that aren't 171 feet. Yet in the sim, >all< elevation points are brought to the same 254 feet by the elevation parameter built into the flatten poly.-------Justinhttp://www.fsgenesis.netHigh Quality Scenery for FS200x

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Thanks Justin. Trouble is, I like your mesh too much! Can't fly without it, which is why I was even considering bothering with this. Thanks for the advice and the wonderful mesh. Do you think any of this will be more flexible in the next version of FS, FSX?

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The flat airport problem is just one of the trade-offs in using high-res terrain, one that most have chosen to live with. To do otherwise is to throw the baby out with the bathwater.Concerning FSX, there's not much I can say without biting the hand that feeds us. Yes, I would expect a bit more flexibility, but maybe not. :-) Let's just say that I have actively lobbied for a solution, and will continue to do so.-------Justinhttp://www.fsgenesis.netHigh Quality Scenery for FS200x

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Hi there,aside from the issue with flat runways it's also possible (and quite common) that the airfield is not at its correct position. The FS team used the official AirNav data but there are no accuracy standards for reporting the airfield's center position and many of the reported coordinates of the smaller fields are hundreds or even thousands of feet off. This may not sound like much but makes a big difference in a mountainous environment. For example, in my Columbia River Gorge project I got rid of almost all of the plateau/trench issues simply by moving the airfields to their correct position (based on georeferenced maps and airphotos).Unfortunately, as Justin indicates, the procedure for moving airfields is actually not all that simple because several files are involved, some of which contain many different airfields at once. Anyone interested in this approach can find a step-by-step description (and discussion) in this thread: http://discuss.projectai.com/index.php?topic=35920.0 Cheers, Holger

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You could try a utility such as FstFlatten which is free - try searching the library. This doesn't change any .bgl files but creates a separate specific .bgl file that you can put into addon SceneryScenery.It also allows the creation of general polygonal flatten areas. This can be particularly useful in enabling the flattened area to be better match the surrounding area.

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I guess it's possible to build sloping runways and taxiways, the problem is that there isn't any way to get AI aircraft to follow those. The AI like to be level. Sloping flattens (LWM3) exist and could be used to better work the transition between a flat airport flatten and the surrounding mesh. I don't know if anyone has done this? One thing I've done is to cut back the flatten area from the default. Sometimes it extends out way too far. the problem with this is you have to edit the default FL file and there is no good way to distribute this edited FL.scott s..

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Hi there,I recently experimented for the first time with overwriting an existing airport flatten with sloped LWM3 polys and it worked well though it's a bit of a trial-and-error procedure. In my case I had moved the airfield into its correct position and at its correct altitude (150ft less than the default), which left the default's plateau standing and blocking one end of the new airfield. Editing the default files wasn't an option in this case so I started placing LWM3s and managed to get rid of the plateau and create a decent-looking slope to the surrounding terrain. The important thing is to manage the display priority of the various flattens, otherwise the sloped LWMs will interfere with the flattens of the airfield or nearby water bodies. For example, LWM3 seems to always overwrite LWM2 flattens, so I had to make the flatten for my new airfield LWM3 as well (to achieve this in SBuilder all you have to do is make a minimal change in elevation to one point of the flatten, e.g. +/- 1 cm, which means you get a LWM3 yet don't end up with a sloped airfield).For smaller airfields that don't need to have AI traffic, working with LWM3 sloped runways is great fun for flying. We implemented a few of those in the Vancouver+ project and users considered that as one of the best features of the whole package. I'm sure I'll be using sloped runways more frequently in future projects ;-)Cheers, Holger

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Thanks, Holger, it's good to here some one with some experience trying this out. This is the first I've heard about the LWM3 vs LWM2 priority. Something to be on the lookout for.scott s..

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