Merging flat airports into hi res terrain

[Guest Robs]

Hi,I am wondering if anyone can help with the problem shown in the piccy below. This is an example which happens to be RAF Lyneham.It is where high res real world terrain meets FS9 (FS2004)'s flat earth society. FS9 assumes all airfields are completely flat which in real life they aren't which means that there are large mismatches and cliffs around the airport.(I don't have FSX but I believe a reduced version of this problem still exists as airfields are flat but sloping)Anyway is there an easy to use utility that could creat a mini mesh around an airfield which could merge from the flat airport into the high res terrain but reducing gradients or interpolating and smoothing out to 1/2 mile around the airport. Not fully accurate but better than the cliffs.(I have done no mesh work before so utilities have to be beginner but savvy suitable)I say minimesh because it would be easy to put in as a high priority and then remove but any solution would be considered except taking out the high res terrain or nice add on airport.Ideas to solve appreciated. I can't be the only one who has come across this.Rob.

[mgh 89]

I can't really help with the default airfields. However, when creating new airfields I can overcome this problem by carefully tailoring the flattened area to match the terrain - I use the free FstFlatten application to do this. It did need a certain amount of trial and error to make the results look acceptable. I imagine the time and effort required explains why this isn't done generally for all airfields.

[Guest Robs]

I have a couple of "flatten" utilities which can reduce the effects of terrain-flat airport mismatch.(I have flattex)In some cases this can work well with just little bumps and not cliffs but in others you just can't flatten out the problem.(The terrain has such a gradient that a cliff is inevitable)So I was hoping a mesh creation utilitie that could smooth from the flat airport into the high res terrain.I was thinking the utility might create a flat circle of specified diameter and then read the existing terrain and apply a smoothing algorithm (gradient limit, or cubic spline) into the terrain at a specified distance. The output could be a minimesh that you could add in and keep/reject at choice.I think this is possible...unfortunatly I have no idea how to approach this!!! I have no idea how to do this.How do mesh people do the meshes? If a simple utility could be written to do this then I think it would help many people!Maybe one has been written? Please let me know.As I said I don't have FSX but I believe although the problem is reduced it is still there and I think an FSX utility could be very similar.

[RobdeVries 28]

That's a thought which 'haunts'my mind since high res mesh was introduced.But I think only some developers might have the knowlodge to answer that question. One of them is of course Holger Sandmann or Steve Greenwood. I'll try to point Holger to this thread. I haven't heard from Steve Greenwood in a long time and his site is down..EDIT: I did a search and the forum search came up with this:http://forums.avsim.net/dcboard.php?az=pri...24&topic_id=843. The conclusion seems that Ground2k(4) has a remesh function..Rob "Holland&Holland" de Vries http://fool.exler.ru/sm/fly2.gif"To go up, pull the stick back. To go down, pull the stick back harder"

[Holger 0]

Hi guys,actually, G2K4's remesh option is not a good choice because its "microflattens" lead to stepped terrain, it requires specific TMVL settings and, with larger areas adjusted in this manner, may overwhelm FS and cause CTDs.The cleanest approach is to remove the default flatten, adjust the airport's position and altitude (both are often incorrect, specifically for smaller airfields), and create a new flatten. However, in FS9 this is a rather messy process due to the way the various flatten and airfield data files are organized. See http://www.projectai.com/discuss/index.php?topic=35920.0An alternative that others and myself have started using are sloped flattens, or LWM3 polygons. These were introduced in FS9 to allow for gradually sloping rivers but they also work as land masks and can be used to deal with plateaus or trenches. SBuilder - http://www.ptsim.com/forum/forum.asp?FORUM_ID=18 - allows for the creation of LWM3s because each point of a polygon can be assigned a specific elevation. It's still a fairly tedious process due to some quirks with FS9's terrain display engine but it does work quite well. Our VictoriaPlus http://library.avsim.net/esearch.php?CatID...scen&DLID=95203 as well as Don Grovetine's CYYJ http://library.avsim.net/esearch.php?CatID...scen&DLID=97316 use LWM3s to smooth airport and shoreline "cliffs".Below is a SBuilder screenshot showing the main airport flatten (the big gray poly) surrounded by small LWM3 sloped flattens. SBuilder connects directly to the sim so you can slew to the locations you'd like your flattens to be and determine the point altitudes.Like I said, not exactly quick and dirty but it works.Cheers, Holgerhttp://forums.avsim.net/user_files/167375.jpg

[Holger 0]

Me again,as for the question about how terrain data is being compiled into FS mesh files here's the active link to Steve Greenwood's website: http://home.earthlink.net/~smgreenwood/welcome.shtmlI also recall that someone was working on a utility to automatically adjust terrain data to airport flattens but this was a couple of years ago and the utility got never published. If I remember correctly the main issue was that it required processing of source elevation data, which made it not any easier to use than adding LWM3s or manipulating the flatten files.Actually, ACES used a similar automated approach to deal with these kinds of situations in FSX, at least that's what they showed us in the Beta forum. However, I'm not sure if they actually retained this method. If they did those adjustments are compiled directly into the FSX default terrain mesh.Cheers, Holger

[Guest Robs]

Hi All,I have some reading and learning to do. I will follow all the links. Thanks for the pointers. It's gonna take a while.On some airports flatten just cannot do the job however carefully you do it due to the way the ground undulates. The particular airports I am interested in are not default airports by aftermarket add on airports. They are at the correct height. The terrain is UK VFR terrain with UK VF photo textures.Sbuilder with it's "Flatten" polygons, although a bit of a compromise, could be made to work if you bothered with enough polygons. We need new terminology for sloping flattens...slopens?However there may be a snag. If this is not a mesh polygon but an object polygon then you have to give it a texture like a building or other object? This would be a problem in my case as I am using VFR phototextures on the ground and a grass texture on the polygons would highlight the problem and not reduce it.Could someone let me know if this is the case?(The airfield designers get around this by following the airfield fence line and putting a texture up to this...as airfield in UK are mown grass then this looks great and not a blot on the VFR photo landscape)I might still give Sbuilder a go to play around...if I am confident that I can remove any hamfisted results.I still think the idea solution is with a mini mesh. I don't really want to adjust the default or installed mesh but read, say a 3 mile circle around the airfield and process this somehow (a cubic spline with zero gradient matching the gradient at x distance from the airfield would be preety good). This would then be fine with phototextures installed.I might email Steve Greenwood with this problem.Anymore suggestions?Rob.

[scott967 62]

I have done the "mini-mesh" for symflyers KLAS and FSG 38m mesh. the first step is to carefully consider the existing flatten (either the default LWM in the FL9 file, or the Area16N or scenery.cfg Flatten= entries). In many cases, the flattens are bigger than needed, which can emphasize the plateau problem.Once I have the flatten smaller, I d/led the USGS NED data for KLAS area. Using sbuilder, I created the mesh bmp file. This bmp uses the red (msb) and green (lsb) channels to store the 16 bit elevation data. I works OK as long as the elevation is +/- 256 meters, though if you "roll over" the green channel it is more work. But so far that is the best means I have found of getting a graphic I can edit. I load the bmp into GIMP graphic editor. First I set the flatten elevation and area, then apply a gradient between the flatten elevation and the actual terrain elevation. It very much trial and error -- I haven't found an easy way to auto apply an appropriate gradient (Any ideas?)Here is the mesh with the flatten mapped out on it:http://forums.avsim.net/user_files/167410.jpgthis is what it looks like after doing a gradient:http://forums.avsim.net/user_files/167409.jpgYou can see I was working on the eastern edge the most -- where the plateau is obvious. You can still see some flatten plateau on the southern edge. I've since blended that out some too. Once I got it I then built replacement mesh in sbuilder. the problem is it is too tedious unless you really, really want to do it.scott s..

[Guest Keyno-onyeK]

Hey scott, can what you've done be d/l and installed into anyones FS9 and solve the KLAS/FSGenMesh Plateau mess?I sure hope the answer is yes.