A great big hole in my knowledge

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I've been accused of many things, but never of pretending to know something when I don't. So here goes:I'm new to scenery design, but in creating my first scenery for FS2002, I've learned a whole lot about how things go together. I can make 3D objects in Gmax, place them where I want and create textures that are, in my own humble opinion, pretty nice looking. I've even got a method for creating pilot-controlled lighting on my airstrip that seems to work. But there's one aspect to scenery design that has me baffled... ground textures. Or more accurately, how in the world to approach the problem. I've looked into creating ground detailing several ways; using Aiport for Windows to create ground polys, using gmax to do the same, utilizing TMF decals for mesh-clinging textures and using TerraBuilder to just replace the groundwork in my entire scenery.There are drawbacks to the poly method that include having to flatten the ground around them, which seems to be an old-fashioned approach and limits how "real" a Alaskan bush airbase, for instance, can look. But in trying to learn about TMF decals and/or TerraBuilder I keep running into this great, gaping hole in my knowledge. What is a LOD? And how does it relate to my scenery designs? For the life of me I can't find a single source that assumes no knowledge of this issue and explains how it works. I'd be very happy to share any knowledge I have of creating realistic textures or using Gmax in exchange for a simple discussion of terrain LODs and creating photo-realistic terrain textures and groundwork.And please, please don't respond that I should read the FS2000 Terrain SDK documentation. Microsoft has a particular talent when it comes to not being able to express themselves in non-programmer terms. When a designer like myself comes across a document that begins with references to unsigned 16-bit integers and floating point calculations, things go downhill in a hurry. I've read everything they've published on the subject of scenery design and terrain creation, and I'm not any clearer than when I started. It's very frustrating, because I can normally learn just about anything I set my mind to by doing research, and I just can't find anything to research here!Thanks for listening to my rant.Bill Womack

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Bill,Do a search for "Resample Method" or my name or Bob B (bob5568) and you eventually find a discussion of some of what you want to know. I am by no means an expert or anywhere close to it, but I do know an LOD is Level Of Detail. There are corresponding numbers that designate what Level of Detail it is. I think that the smallest LOD that you can place custom ground textures on is and LOD13. I DO NOT know the dimensions of these squares (rectangles) but they are out there somewhere. the TerraBuilder forum should have all of this info. But you've search there and have found nothing? I don't know what method you would want to attempt because it all depends on the amount of ground you want to cover. I am working on a scenery (my first) and ran into the same problem. I was at first just going to use TMF decals to replace the airport ground area, but that wasn't working out too well, and would have taken forever. Then kind rhumbaflappy suggested the custom ground texture methos, and I figured out how to do it and i believe it is the best methos to use when covering larger areas. I dont know how many LOD13 areas I have covered but it is definitely several!If you use the custom ground texure method, ther are instructions in the thread "The Resample Method". But read Bob's advice too! Get an aerial picture of your scenery that is a higher resolution than 4 meters/pixel and then resample that using the program Bob talks about. Then use that as your resample ground texture source. That way you will have more resolution once the textures are used in FS. I hope you have a paint program if you go this route!Hope this helps a little.

[Guest]

Hi Bill, Tom Lassiter has steered you to good threads of information for making meshclinging textures. the only other way of decorating the ground that I know of is the work that Rhumbaflappy, Lee, and Christian are working on, applying decals using tmf code. Of course I mean the only ways that allow the ground to be non-flat.LOD is easy to understand. Think of the world as an orange with the stem aligned with the poles. If you slice the orange in half at the equator, and then seperate it into sections that equal 1/3 of the orange (at 0, +120, and -120 degrees longitude), you've divided the world into 6 sections, that is LOD 0. Each time you add a level of detail, you halve the size (both in lat and longitude) of each piece. so...lod 1 is 12 sections, we now slice the world at 0, +45, -45 latitude, and 0, +/-60, +/-120 and 180. keep doing that, each time halving the size of the section until you reach lod 13, and that is the locked size of each texture coverage for photoreal terrain using the microsoft tools ("the resample method").How does LOD impact the design process? It comes in because the "resample method" will portray photo real terrain where ever a source file covers (completely) an LOD13 grid. This is why sometimes you can present a source image to the resample process, only to find that part of the photo was ignored. That part failed to completely fill the LOD 13 grids. This means that when I lay out a photo area for the first time, I calculate the location of the grids for that area. This is really easy to do if you have two points of known location. I use the runway ends of an airport I may be designing. Most of the design programs will report a lat/long for the runway ends, like airport, asd, fssc, etc. most of the time your photo will show the runway or at least the scar made by the runway. Once you change the resolution of the photo to 4.8m/pixel, you know how many pixels long the runway is, you know how many degrees difference between the two points in both x and y, (hoping your runway has a fair angle to it, work arounds are needed if your runway is pointing directly ew or ns), so dividing the two numbers gives you degrees/pixel in both x and y. I wrote a simple spreadsheet that calculates the distance in degrees between any point and the nearest nw corner lod13 grid. I can send you that if you wish. With that knowledge you can subtract the lat/long of your runway point from the lat/long of the nearest grid boundary, convert that into pixels using your deg/pixel factor, and then you can draw in a graphics program over your source photo the grid lines that correspond to the nw corner of that grid. You also know the distance in degrees for lat and long of LOD13 using my spreadsheet, which means you can determine the length and width in pixels of each lod13 grid....thus you can offset from the initial two lines the distance for each grid, and result in a grid pattern overlaid on your photo. Now you can tell quite easily what part of the photo will be displayed and what part wont, and how many textures should result from the resample process.Hope that helps, Bob Bernstein

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Tom and Bob,Thanks for taking the time to point me in the right direction! I very much appreciate it. Tom, I'll check out the threads you mentioned. Bob, I'll probably have to re-read your post once or twice, but it's very helpful. I guess the problem is that although I can understand abstractly how LODs work, I don't have a good grasp of how they overlay scenery and are used by FS2002. I'll get there though... this is good information. Oh, and I'd love to have a copy of that spreadsheet. I believe my email is visible through this forum system.thanks again for the enlightenment!-Bill

[rhumbaflappy 113]

Hi Bill.All the info needed to determine locations for TMF water, TMF flattens, TMF lines, or TMF decals can be found by using fsregen], by George Ioannu. I use this program all the time for TMF calculations.The button to click is TMF Calculator. That brings up a window called Christian's Calculator. Type in a coordinate of where you want a decal, go to the bottom and click calculate, and a plethora of information becomes available... including an example of the BGLC code needed for locating these TMF items. FLATTEN_DATA contains the LOD13 quadrant sub-reference.FLATTEN_POINT is the x,y reference within the LOD13 quadrant FLATTEN_GROUP contains the LOD8 quadrant reference.All TMF decals ( all flattens, water, anti-water, lines, CFS2 lines/polys, decals ) use the LOD8 quadrant for location. LOD8 splits the entire world into a grid of North to South, West to East, 512x768 quadrants... for a total of 393216 LOD8 quadrants. The numbering is 0-511 and 0-767. Christian Stock's TMFMacros.inc places the locational LOD8 GROUP elements as y,x rather than the more common x,y. TMFs then use a further subdivision of the LOD8 GROUP area split into a 32x32 grid ( which corresponds to an LOD13 DATA size ). The numbering for these in the BGLC code is confusing at first, but George's tool makes understanding this unnecessary. There are 3 entries... x, sub-x, y. x splits the LOD8 group, in the longitudinal direction 8 ways ( 0-7 ), West to East.sub-x splits the x division into 4 sub-parts ( 0-3 ). The total longitudinal split of the LOD8 GROUP is now 1/32... an LOD13 size.y splits the LOD8 GROUP latitudinally into 32 parts, directly ( 0-31 ), North to South. The LOD13 area is further split into a 255x255 POINT grid ( numbered 1 to 255... 0 is accepted but may lead to "visual artifacts" in the decal ). This definition means a single POINT represents 4.8 meters square, at the equator ( approaching 0 by 0 at the poles ).BGLC code can span several LOD8 GROUPs, and several LOD13 DATA sub-areas.The only other locational info needed for BGLC coding are the Header Bounds... same as any traditional Header... I usually give + or - 1 degree each way NSEW , and round off the Latitude/Longitude, to envelope the LOD8 GROUP areas.There may be alterations to the basic set of BGLC macros in the future, as more knowledge is developed, and user-friendliness becomes a greater issue. I think for now, we're better off sticking to Christian's macro definitions in TMFMacros.inc, and the additions I made with CFS2TMFmacros.inc[/i. In fact, the reason we have 2 sets of include files is I didn't want to mess with Christian's set. We could end up with 100 different variations of macro files! This way, we all have the same terms and definitions to discuss.That's all there is and there ain't no more. :)P.S.Sorry I didn't respond directly to the e-mail you sent me about this, but the forum allows everyone to get an explanation.Dick

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Rhumbaflappy! What can I say? Thanks for the EXCELLENT reference! I've learned more in the last 24 hours of messages by the likes of you, Tom and Bob than I might have in a month or more of digging on my own. That is to say, I still have a lot of cloudy, dark parts in my understanding, but I can see the sun poking through now, and that's exciting. I'm now confident that I can at least plot where I want my decals to go in both the LOD13 and LOD8 quads, so that's a beginning. I'm going to go through now and re-read some of the other posts you've made on the subject. Once my brain gets interested in something like this, I can't let go of it... I've been (literally) losing sleep for a week trying to get a handle on it. This will be a big help.thx,Bill