• FS Global 2008

    FS Global 2008 For FS2004 And FSX

    By Andrew Herd (1 May 2007)

    FSX brings fundamental changes to the virtual landscape we know so well, chief among which is that FS world is no longer flat and that the accuracy of the mesh has been improved. That's the good news. The bad news is that the improvement isn't uniform and that some areas have been treated better than others; I am sure it will come as no surprise that these are parts of the world where significant numbers of Flight Simulator purchases are made. The previous high quality US mesh is still in place, but FSX uses 76 meter resolution Shuttle Radar Topography (SRTM) data to cover Europe, Japan, Australia and part of the Himalayas - the rest of the world has to make do with 612 meter mesh, with the result that the landscape rarely looks even semi-realistic. FS Global 2008 is an FS2004 and FSX addon which rolls out enhanced 76 meter SRTM mesh to the FS world lying in between latitudes 60 degrees north and 60 degrees south..

    First of all, what is mesh? Flight Simulator, and it doesn't matter which of the more recent versions you are talking about, creates its landscape by laying terrain texture tiles across an elevation mesh, which forms the mountains, valleys and plains. As I remarked above, the accuracy of the mesh varies from one part of the world to another, which means that the scenery in the Grand Canyon is much more convincing to fly over than say, Malawi. This has annoyed simmers since the wire-frame scenery days and if you want to see what the virtual world looked like only half a dozen years ago, follow this link and take a look at the screenshots from FS2000. As you can see in the screenshot pair below, even when you are using FSX, quite a bit of Asia still looks like it did back then and we have a lot to thank the early pioneers of mesh addons for.

    FS Global 2008 is available in boxed format only - for good reason, because installing it gobbles up roughly the same amount of hard disk as a full FSX installation does, which is around 13 Gb. The box contains four DVDs - note not CDs - two of which are for the FS2004 installation and two for FSX. The reason for this apparent duplication is because FS2004 and FSX require different data because of technical differences in the way they treat mesh, not least the fact that in FS2004 the world is flat and in FSX world it is round, which means that if you want to use FS Global 2008 with both versions of the sim, you have no choice but to install it twice. Gulp.

    The installation process was trouble-free, but as I am sure you can imagine, 13 gigs takes a looooong time to transfer, even with a 16 x DVD-ROM drive. Paper documentation is restricted to a fold-out slipped in among the disks, but there is a four page pdf which goes into more depth on the first DVD and I would suggest reading this before you get going. Just about the only gotcha is that there is no way to do a partial install, so if you don't have enough free disk space, you won't be able to install the product; and it is worth mentioning that the second DVD in each set is double-sided, so at some stage in the installation you will be asked to eject and flip it. Most DVD drives should be able to handle this type of media, which has been around for as long as I can remember.

    The first thing to say about the product is that the days when mesh addons transformed the entire FS world are gone, because the default mesh is more than acceptable in the 'high res' areas I mentioned at the beginning of the review. This isn't to say that FS Global 2008 doesn't make a startling difference - it does, but as you can see in the screenshots above, it is only the case in the low-res areas. During the review I set up FSX to show the mesh at its highest possible quality settings, saved a flight after taking a screenshot of the default landscape, installed FS Global 2008, reloaded the same flights and repeated the screenshots, so the only differences between the pictures are accounted for by different placement of clounds. The top pair of shots show the view on departure from Jalalabad in Afghanistan, the second row show the King Air flying out of Tribhuvan International, over the Himalayas, and the final row show a departure from Redding in California towards Mount Shasta.

    In each case, the default FSX scenery screenshot is on the left and the same shot with FS Global 2008 installed is on the right. The changes, as you might expect in high-res areas like the US and the Himalayas, are quite subtle, because in each case we are looking at the best mesh FSX has to offer, but the interesting thing is that even in this (rather harsh) test, the FS Global mesh is noticeably better. The only reason I can put forward to account for this lies in the way the SRTM data has been dealt with - it looks as if the FS Global post-processing has generated more intersections than Microsoft's team did. This efffect is more obvious when you are flying across the landscape than it is in the screenshots, but suffice it to say that mesh junkies will notice the difference.

    As evidence of this, I offer the bottom pair of screenshots. As befits Northern California, we have a lovely sunny day, courtesy of Microsoft on the left and FS Global on the right. But hold on a second, where have those islands come from? Yep, even in a high resolution area of US scenery, FS Global does make a difference, and it is hard to fly for any period of time without noticing it. Go outside the FSX 76 meter mesh area and you can imagine what sort of changes you will see - whole ranges of hills and even mountains appear that FSX forgot. Look again at that top pair of shots - vast areas of the FSX world look like the screenshot on the left, when FS Global can make them look like the screenshot on the right.

    Needless to say, there are disadvantages to installing third party mesh into Flight Simulator, but these are less of a problem with FSX than they are with FS2004. Using addon mesh in FS2004 improves the landscape at the expense of creating a lot of elevation problems around airports - the reason being that FS2004 uses 'flattening' codes to make the area around runway complexes, er... flat. As long as you stay with the default mesh, the vast majority of airports sit neatly on the terrain, looking as if they belong there, but install a new mesh and the flattening codes are liable to conflict with the mesh data. This can be problematic in mountainous areas, because the coarse grained mesh which FS2004 uses may put a piece of land within an airport boundary dozens of feet below or above where it should be - a problem which is exacerbated by the fact that many runways have a slope in one direction or another and Flight Simulator likes 'em level. So if you install a new mesh in FS2004, you are likely to encounter quite a few airports sitting on mesas (not so bad, as long as you don't undershoot), or in depressions, which makes approaches considerably more challenging. FSX, on the other hand, has the mesa/depression problem built-in, thanks to the change from a flat to a round world. Install a new mesh and all that happens in FSX is that you get a different set of airports at the wrong elevation.

    Much the same comments apply to roads, lakes, rivers and coastlines. Because some FSX and FS2004 lakes have been set to the wrong elevation, you can end up with some strange effects after installing an addon mesh and it was no surprise to come across a few of these when I installed FS Global 2008. Your mileage will vary in this respect, depending on whether you use FS2004 or FSX. In the high resolution FSX areas, the problem is hardly noticeable, because the default mesh is already quite accurate and the road and river data combines with it well - but when you put addon mesh in areas which were 'low resolution' in Flight Simulator, anything can happen. In FS2004 especially, but also in FSX, you can expect to see the occasional lake half way up a hillside, roads flying through thin air and the occasional mismatch at coastlines. Given the thousands of rivers, roads and lakes represented in Flight Simulator, it just isn't practical for third party developers to do anything about this; and who can blame them, when Microsoft have left FSX cursed with the same problem as it comes out of the box?

    FSX being the beast it is, I am sure that readers will be keen to know what FS Global 2008 does to frame rates and the answer is that it doesn't have a noticeable impact, unless you are used to flying in areas which are low-res in the default FSX installation. In this case - and the same applies to FS2004 - you will see a drop in frame rates, as Flight Simulator has to spend more effort generating more detailed terrain. But apart from that, if you are planning on flying outside the high resolution areas of Flight Simulator's mesh coverage, there is no downside to FS Global 2008 and the product is definitely worth a look.

    Andrew Herd
    andy@flightsim.com

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