Introduction To Terrain Mesh
Unlike landclass, which determines what type of land will be displayed on top of the land (whether it will be forest, city, or open field), terrain mesh determines the shape of the land itself (whether it will be valley, plain, or mountain).
Flight Simulator has come a long way since the early days, when the sim was based in Chicago. I lived in Chicago for six years and have fond memories of that city. But Illinois is flat, flat, flat and for the first few years, so was the world of Flight Simulator. That has changed. Today, Flight Simulator covers the whole globe, from the heights of Mt. Everest to the depths of the Dead Sea.
Still there are what theologians call “degrees of glory.” In the language of terrain mesh, those degrees are called “levels of detail” (LODs for short). LOD2 has twice as much detail as LOD1, and LOD3 has twice as much detail as LOD2. So, as a rule, you want your LOD numbers to be high. In FS2004, most of the world’s hills, valleys, and plains were rendered in LOD5, which sounds better than it looks. With LOD5 mesh, you will get the correct height (above sea level) for an area 1.2 kilometers on each side (about three-fifths of a square mile). But within that area—that three-fifths of a square mile—you won’t see any variation at all: no little hills or ravines, no cracks, crevices, or outcroppings. LOD5 mesh will show you the rough contours of the land, but none of its nuances.
With FSX, the standard resolution has doubled to LOD6. (That’s the standard resolution for the whole world. It’s much higher for Europe, North America, Japan, and Australia.) Where before, the sim registered the height of terrain every 1,223 meters, now it checks twice as often, every 611 meters. (Notice that when the LOD number goes up by one, the meter count drops by half.) This is a big improvement, but for VFR pilots it’s not enough: valleys can sag now but they still don’t plunge; mountains swell but don’t stand out.
For that we still need add-on terrain mesh. My first-ever payware for FS2004 was a terrain mesh from FSGenesis (FSG for short), and I am still using it three years later almost everywhere I fly. FSG has been a member of the flightsim community for a long time now and its founder, Justin Tyme, is a well known presence on several flightsim forums, including AVSIM's. When someone new to Flight Simulator asks which add-ons to buy first, Tyme’s terrain mesh is inevitably one of the first suggestions that people make, because it improves the look of the sim dramatically, doesn’t cost a lot, and is easy to install.
Currently, Tyme has two products for FSX: high-resolution terrain mesh for North America, and what I am going to call medium-resolution terrain mesh for Everywhere Else. I am reviewing the Everywhere Else product, which you can either purchase on the FSG website (in download or disc form) or through Abacus, which has been selling computer books and products for almost thirty years. What FSG calls “World Terrain Mesh for FSX,” Abacus markets as “World Extreme Landscapes.”
I tested the Abacus “World Extreme Landscapes” version, which I’ll call WEL for short; how it differs from the version on FSG’s own website will be described briefly at the end. My main task here is to show what the product looks like and how it compares with the default terrain mesh in FSX.
Installation and Documentation
WEL version 2 ships on a single DVD. In addition to the DVD, there is also a piece of paper the size of a postcard: that is the documentation. With some add-ons, this would be a bad sign, but with WEL the postcard is all you need. The installation procedure is extremely simple and, once the product is on your hard disk, you can pretty much forget about it. The only thing you might need to adjust is your Mesh Resolution (on the scenery tab of your FSX display settings); with WEL, you want to set this for 76m or better.
Comparisons With The Default Mesh
As explained above, World Extreme Landscapes covers the whole world except North America. To test it, I wrote down the names of a dozen locations in different countries and then set up screenshots for each, using the default mesh. I then saved the flights, installed WEL, and made a second screenshot for each same location.
How did I choose the locations? First, because this is a product for the whole world, I needed at least one location from every continent in the coverage area (i.e., all of the continents except North America and Antarctica). Second, because this is a terrain product, I needed to pick regions of the world that show terrain. There would be no point in comparing screenshots of a flat city (such as London or Paris), because they look the same no matter what resolution of terrain mesh you use.
Here is the list I ended up with: Asmara (Eritrea), Budapest (Hungary), Canberra (Australia), the Dead Sea (Israel), Edinburgh (Scotland), Gerik (Malaysia), Islamabad (Pakistan), Paro (Bhutan), Santiago (Chile), Sapporo (Japan), Sunnmore (Norway), Tashkent (Uzbekistan), Wellington (New Zealand), and Yangzong Hai (China).
If I didn’t include where you live, I apologize. And, yes, I’m aware that the United States Coast Guard is not authorized to conduct operations in any of the regions depicted here.
The results of this comparison can be summarized quickly. In regions where the default mesh is already good—Europe, Australia, and apparently New Zealand—there is little or no discernible difference. But for Asia, Africa, and South America, the WEL screenshots are noticeably more nuanced: peaks sharpen into points, and mountainsides show ripples and folds.
There is an exception to this rule. Almost all terrain mesh, including the default mesh, is based on publicly-available data gathered in 2000 by the Shuttle Radar Topography Mission (SRTM). This data are not perfect: there are spikes and depressions everywhere, which had to be fixed manually (if they were fixed at all). The National Geospatial Intelligence Agency has now released an edited version of this dataset, SRTM2, which cleans up many of these errors, and for WEL version 2, Tyme has taken advantage of this.
But even the edited shuttle data still give errors in regions with dense mountains. For these, there are better, more accurate datasets in old-fashioned topographical survey maps; but someone had to undertake the painstaking labor of compiling it. That someone is Jonathan de Ferranti, who released his work last year. The result, in the case of WEL, is crisper, more well defined peaks in several mountain ranges around the world: ie. the Himalayas, the Alps (where the resolution actually shoots up to LOD11), Scandinavia, the Pyrenees, the Caucasus, New Zealand, and parts of Africa and Japan.
New Zealand is an interesting case. For most of that country, the default mesh would now seem to be quite adequate judging from the screenshots of Wellington. The exception -- and it is something of a notorious one among meshmakers -- is Milford Sound (NZMF). If you have seen Peter Jackson’s Fellowship of the Ring movie, then you have seen Milford Sound. It is the stone canyon through which the river Anduin winds, and where we see the giant Argonath, those weathered statues of ancient kings. In the default scenery, Milford Sound is quite recognizable, but the grandeur of it is softened. Tyme’s version is both more detailed and more striking.
What’s happened here is that the airport and river have been assigned the same elevation as the surrounding land, which just happens to be 830 feet too high! Tyme’s mesh can reset the land to its proper height (ten feet or so above sea level), but the airport and river are programmed separately, so fixing the mesh doesn’t affect them.
How WEL Version 2 Differs from WEL Version 1
WEL version 2 differs from version 1 in four important ways:
1. Version 1 worked with FS2002, FS2004, and FSX. Version 2 only works with FSX.
2. Tyme doesn’t stand still; since WEL version 1 was published, he has been refining his mesh to make use of new data as they become available, and version 2 incorporates those refinements.
3. Version 2 takes much less disk space. Whereas version 1 came on three DVDs and required 14 gigabytes of hard disk space, version 2 comes on one DVD and takes only 4 gigabytes of disk space. With FSX, terrain information can be stored in compressed form; this brings the file sizes down dramatically.
4. Version 2 eliminates the need for so-called “buffer mesh.” With previous versions of Flight Simulator, gaps were sometimes visible in the terrain when you used high-resolution mesh. The solution was to add one or more layers of low-resolution mesh that would fill in the gaps. With version 2 of WEL, the buffer layers are already built-in.
Some products, when they get better, get more expensive. This one hasn’t. On the fsgenesis.net website, it is US$20 for the download version and US$25 for the DVD (shipping is free). An advantage of purchasing it direct from FSG is that when Tyme issues updates, the download is usually free.
The Abacus version, on DVD only, sells for US$30 plus $7 shipping. (There is a substantial discount for purchasers of version 1: the total price is US$17.50 and shipping is free.) The advantage of the Abacus version is extra features. In addition to the terrain mesh, you also get an aircraft and 23 saved flights that highlight the world’s mountain ranges.
For example, one flight “takes you from Chile across the Andes into Argentina." Another flight starts you off at Kathmandu, Nepal and then turns you loose on the Himalayas. The aircraft that comes bundled with the Abacus version is a Socata TB21 Trinidad, modeled for Flight Simulator by Premier Aircraft Design (PAD). Like everything that PAD makes, it’s a good piece of craftsmanship, but I’m not going to describe it here, because you can download it yourself from premaircraft.com; it’s freeware.
Should you buy World Extreme Landscapes Version 2? I don’t usually pose this question directly, because a lot depends on what kind of flying you do and what you’re interested in. If you’re indifferent to scenery (and some people are), then I suppose you can let this one pass. Ditto if you never fly outside of North America.
But if, like me, you use Flight Simulator to explore the world (and not just its airports), then WEL is an obvious BUY. It’s not expensive and it’s easy to install. It won’t fix rivers or coastlines; and for Europe, Australia, and Japan, you won’t notice a difference except in certain regions (which happen to include most of the more famous mountain ranges). But for Africa, South America, Asia, and the Pacific islands, there is no contest. The World Extreme Landscapes terrain is both more well defined than the default mesh and more detailed. It makes the land look like itself.
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