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scott967

How to move an airport boundary

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This is my first post to the forum. I have been playing with AFCAD for some time now but have only recently decided to start doing something more with scenery design. I am beginning to understand how the different scenery components tie together, thanks largely to LWMViewer which gives a clear indication of what each file contributes to scenery.I am working on one airport that is modeled incorrectly in FS9. The navaids are in the perfect positions but the runways, taxiways, aprons, buildings etc are about 200m out of their actual position. This makes instrument approaches more challenging than they should be. So, I have moved it all into the correct position. The thing I'd now like to do is move the airport boundary, flatten, and exclude the existing flatten and boundary from the FS9 defaults. I think it's called a boundary - it's the information recorded in ABxxxxxx.BGL that causes default grass texture to be applied to a specified area, usually around airports. I have created a flatten which compiled with SCASM so this is no problem. However, the boundary seems to be something a little more tricky. I'm sure there's an easy way to do it using SCASM. The flatten file is as follows:; based on the FSTflatten process; Copyright(www.fs-traveler.com)Header ( 1 -40.318115 -40.326602 175.627891 175.601231 )LatRange ( -40.326602 -40.318115 )Set ( areamx 64 )Area16N Elevation ( 46 -40.319067 175.602922 -40.320934 175.602559 -40.320953 175.611832 -40.322654 175.612171 -40.325169 175.616772 -40.324522 175.622849 -40.322469 175.625996 -40.319011 175.626504 )END16In theory, assuming the format is similar, this could easily be converted into a boundary. What is the best way to do this?And how about excluding the defaults? Using a standard exclude xml file compiled as a BGL has no effect on ground textures so I assume there must be another way.Any help is much appreciated.RegardsRichard

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Hello Richard,Welcome to the forum and to scenery design.To remove the grass skirting for your airport, you will have to create a terrain exclude. XML excludes do not remove terrain elements.Since I assume that you are using FS 9, then you can use a couple of programs for this purpose - try either Ground2K4 by Christian Fumey or SBuilder by Luis de S

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Hi LuisThanks for your reply. That worked a treat. I am using FS9 and used SBuilder. Excludes are strange things I've found. They work, but when I append the exclude BGL into an existing SBuilder project, I don't see them! I assume this is normal.I have another question regarding removal of lakes. I gather that using excludes for this doesn't work:"With VTP scenery there is also a potential for conflict when several designers modify the same region. The problem here is related with the depressions of river streams. By using the "Coexist/Replace" flag you exclude the default items. However this exclusion will not remove the depressions of the original streams (something similar to the altitudes of lakes in LWM scenery).If the only way to remove the left depressions is to alter the default scenery, you should provide a file for a complete LOD8 square (or Cell). This applies to both LWM and VTP scenery. There is a small programme that merges complete Cells with a default LOD5 VTP or LWM BGL. Search the AVSIM Scenery Design Forum for "BGLPatch". This programme is capable of installing and uninstalling the reworked Cell."This is from the SBuilder help file and is exactly the problem I am having. An exclude polygon placed above a lake in the default scenery doesn't exclude it. Is there a recommended way of dealing with this problem?RegardsRichard

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I put a tutorial on using sbuilder and lwmviewer in the avsim library. You might want to have a look at it, though it sounds like you have doped it out already.On the question of exclusions, there are terrain exclusions and object exclusions. Object exclusions use the xml bglcomp-style scenery methods.As you found out, you can change a watermask area back to landmask, but you can't eliminate the flatten on lakes or airports this way. for my personal use I use lwmviewer to disassemble the default file and I hand edit out the flatten or lwm polys that are causing my problem. You could also append the whole file into sbuilder and delete the polys in there, then compile it back but that way you are in effect copyig the MS files which probably isn't a good idea for release. I haven't really tied the BGLpatch method. In theory it would work but I worry about putting it into the hands of users.for moving around airport elements, you might want to have a look at scenegenx. The reason I suggest this is that SGX can import the default AFCAD stuff, plus all the scenery objects that the AFCAD 2.1 program doesn't work with. SGX also allows the use of a background like sbuilder, though the design unit in SGX is meters, not degrees, so you have to use some care in how you prepare a background so that it properly positions.scott s..

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Hi ScottThanks for your help. I'll have a look at the tutorial in due course. There is a bit of a learning curve associated with scenery design, but I now feel I am getting toward the productive side of it.>As you found out, you can change a watermask area back to>landmask, but you can't eliminate the flatten on lakes or>airports this way. for my personal use I use lwmviewer to>disassemble the default file and I hand edit out the flatten>or lwm polys that are causing my problem. You could also>append the whole file into sbuilder and delete the polys in>there, then compile it back but that way you are in effect>copyig the MS files which probably isn't a good idea for>release. I haven't really tied the BGLpatch method. In>theory it would work but I worry about putting it into the>hands of users.If I decompile them with LWMViewer, I get a .bgs file. What do I recompile that file with? I must admit, I'm still a little confused about how, after doing this, I am meant to override the default file. All of the methods you mentioned seem to require permanent modification of the default file, which as you say is not good for release.It may be that one way around this is to actually recreate an entire coastline and LWM BGL for the area I am working in. It wouldn't be THAT difficult, although the hardest part is getting the map data then somehow compiling it in without having to draw it all by hand. On thinking about it though, I realise that I will most probably still be stuck with the problem of the default BGL underneath it all having edges in the wrong place, simply because I can't exclude edges.Or am I totally misunderstanding it?RegardsRichard

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>>If I decompile them with LWMViewer, I get a .bgs file. What do>I recompile that file with? I must admit, I'm still a little>confused about how, after doing this, I am meant to override>the default file. All of the methods you mentioned seem to>require permanent modification of the default file, which as>you say is not good for release.To compile the source back, you need to get the BGLC.exe program from the FS9 sdk, and some macro files , tdfmacros from Dick Ludowise.http://library.avsim.net/download.php?DLID=53313 tdf macros has 2 files, one for the file header and one for the file content macros. If you have any experience with assembly language or even C, you can pretty much dope out the specifics. The source file is broken into LOD8 cells. Within the cell individual polygons are listed by LOD13 numbers. So by getting the LOD8 and LOD 13 positions of the polygons you want to eliminate you can sinply delete them in the source, save the file, and then drag/drop it on bglc.exe.http://forums.avsim.net/user_files/169420.jpgNote that 4 polygons make up the entire flatten above.Of course, you need to disable the default file and replace it with this new one.>It may be that one way around this is to actually recreate an>entire coastline and LWM BGL for the area I am working in. It>wouldn't be THAT difficult, although the hardest part is>getting the map data then somehow compiling it in without>having to draw it all by hand. On thinking about it though, I>realise that I will most probably still be stuck with the>problem of the default BGL underneath it all having edges in>the wrong place, simply because I can't exclude edges.That is in essence what UT USA does. You can see if you look at the Canada border. It renames all the default HP9 files to triple x extension.>>Or am I totally misunderstanding it?No. That's the choice you have: live with the bad flattens in lakes / airports or replace the defaults with your own.scott s..

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