When the full version of FSX became available in October 2006, there were several immediate complaints. The first and most persistent was performance. Users also noticed, however, that even when the sim is running smoothly, there are large deserts in Europe and North America that hadn’t been there in the previous versions.
According to Holger Sandmann, writing in the AVSIM forum, the deserts are actually a by-product of something everyone has praised about the new sim: namely, more detailed ground textures. How did this happen?
Flight Simulator has a finite number of ground textures, which it applies on the basis of something called land classification (landclass for short). Landclass tells the sim which parts of the world are urban highrise, which parts are farm fields, which parts are desert, and which are covered with lava. In FSX, there are about 120 different land types. The system works quite well, and with more detailed ground textures, looks great too. The trouble, as Sandmann explains, is that the new, more detailed ground textures are exposing flaws in the landclass, which hasn’t changed.
We saw something similar a couple years ago, when Allen Kriesman gave us USA Roads. The new, more accurate roads looked great, but they often crossed lakes and rivers in unrealistic ways. The roads were in the right place, but the water wasn’t. The solution for that problem was Kriesman’s Ultimate Terrain, which included accurate water to go with the accurate roads. Now it’s the ground textures that have gotten more accurate, and the result is we can now see more clearly something that was there all along. The default landclass in Flight Simulator is crude in some places and just wrong in others.
At one point, Microsoft intended to fix this for FSX. It didn’t. To remedy this, Cloud9 has introduced the Xclass series of more detailed and accurate landclass products. As of this writing there are four regions available: Europe, USA (not including Hawaii and Alaska), Canada, and Australia. Each region costs US$10. I tested the products for Europe and USA.
Installation and Documentation
Landclass data is very compact, so both downloads were small. Installation was quick and simple. I had some trouble with one of the patches (more on these at the end), but there was a quick fix on the customer support forum and subsequent patches have gone smoothly.
Documentation is minimal. It explains, clearly, how to install the new landclass but it doesn’t explain what landclass does or what this landclass is based on. For patches, a readme file describes what changes have been made since the last version.
The Big Picture
These products are continental in scale. I knew I wouldn’t be able to look at everything, so I chose some sample areas to examine in detail. I started by using one of the SDK tools that ships with FSX Deluxe, a powerful little program called TMFViewer. This shows the landclass in schematic form, as colored squares. Each square represents about one square kilometer of land, and each landclass type has a different color. The advantage of looking at the landclass this way is that you can see larger patterns in the data.
For Europe, I chose five areas to look at: the English Channel, northern Spain, the islands of Sicily and Sardinia, and the Alps. To my knowledge, this is the first third-party landclass for all of Europe, so I compared it with the only thing available: the default landclass that ships with FSX. For the United States (not including Alaska or Hawaii), I chose four regions, each centered on a major city: East Coast (New York), northern California (San Francisco), Nevada (Las Vegas), Midwest (Chicago).
Here is what I found:
With the US, I had another option for comparison: in addition to the default landclass, I also looked at the landclass product for FS9 published by FS Genesis (FSG). A few of the land types have changed since FS9, and some new ones have become available; still, the FS9 landclass does work in FSX. I used the beta version, which is freely available from the FSG website.
The results of this comparison can be quickly summarized. The default landclass, when viewed in this way, is blocky, with large areas of undifferentiated land. In contrast, the Cloud9 and FSG products have a great deal of variation and the shapes that are formed have more detail and nuance to them. What does this mean in the sim? A couple of things. First, the add-on landclasses include a large number of small towns that don’t exist in the default. Second, you will see a greater variety of land types, even in a small area, reflecting the variety of land types in the real world.
I did notice one odd thing about Cloud9’s Europe landclass: nowhere, even in the largest cities, does it make use of the Large City Highrise type (#121). The result, I suspect, is that some of Europe’s cities may look too “short.”
Looking at the big picture, we can see that the Cloud9 products (and, for the United States, the FSG product as well) are more precise than the default landclass. Where the default landclass is coarse-grained, the Cloud9 landclasses are relatively fine-grained.
But are the new products accurate? When you fly over them in the sim, do they look like their real-life counterparts? This question can only be answered on a case-by-case basis, so again I made a series of comparisons, this time of screenshots in the sim. All screenshots were taken on the same virtual day in early December using identical lighting conditions and maximum autogen. Where possible, I also made a comparison with an existing third-party landclass: the beta version of FSG’s landclass product (for the United States) and, for two of the German locations, the landclass that is part of Scenery Germany published by Aerosoft. Both of these are for FS9 and, as I mentioned a moment ago, some of the landclass codes have changed in the new version. Finally, I tried to replicate each screenshot in Google Earth. Another possible point of comparison, which I did not set up, would have been the city landclass that is part of Ultimate Terrain (also for FS9).
For Europe, I made screenshots of the following locations: Bremen (Germany), Brest (France), Cork (Ireland), Innsbruck (Austria), Krizanov (Czech Republic), the Lake District (England), Magdeburg (Germany), Naples (Italy), Nice (France), Perth (Scotland), Thessaloniki (Greece), Trondheim (Norway), and Wasserkuppe (Germany). If I skipped your country, I apologize.
For the United States, I set up screenshot comparisons in Crescent Lake (Maine), The Dalles (Oregon), Duluth (Minnesota), Greenville (North Carolina), Las Vegas (Nevada), Portland (Oregon), Sarasota (Florida), and Urbana (Illinois). Again, if I skipped your state, I apologize.
The results of this comparison are harder to summarize than of our first. In general, we can say again that there is more variety of land types in the add-on landclass products, and that the new elements correspond--roughly--with what we see in Google Earth. In particular, there is more of an attempt to differentiate between the levels and types of buildings within towns. Also, we have a more nuanced sense of how the town interacts with the countryside: which parts of the town are built up, and which are still open fields.
Admittedly, some areas still look flat and boring compared with the equivalent screenshots in Google Earth. Conversely, in places where Google Earth is still using low-resolution photographs, the flightsim version looks more interesting no matter which landclass we use. Finally, the Cloud9 idea of Europe is much greener than the default.
Performance is not a serious issue with these products. Whenever you add detail to the sim, you almost always take a performance hit. (An exception is replacement ground textures, such as Ground Environment or Birds Eye View, and even here performance will drop some if the replacement textures have denser autogen.) But some hits are bigger than others.
In pre-patch FSX, the biggest hit seems to come from autogen. (Complex aircraft are another cause of low framerates, but that was true in the previous version as well.) Many people have pointed out that the lowest autogen setting in FSX is the equivalent of a high setting in FS9, so there is more work for the CPU and graphics card. For my comparison screenshots, I used the highest autogen settings because I wanted to show everything at its best, but I was just snapping pictures, not trying to fly.
Will using Xclass decrease your framerates? I doubt it. If you install Xclass, you will see more varied ground textures and therefore your system will have to process more files, so there is potential for more stuttering. In practice, though, I didn’t notice any difference. The more memory you have on your motherboard and on your video card, the smoother the sim will run. (It seems that for smooth flying in FSX, you need 2 gigabytes of system RAM and 512 megabytes of video memory.) In rural areas, you will encounter more towns with Xclass and therefore more autogen. But the effect will be no worse than passing over a town of comparable size with the default landclass.
I don’t know what would happen if you used Xclass in previous versions (FS2002 or FS2004), but Xclass should be compatible with all sceneries for FSX. Landclass will complement products such as FSG terrain mesh and Ultimate Terrain, but it won’t interfere with them.
This review is short on text, long on pictures. That’s because, with a product like this one, the images are all we care about. The default landclass that ships with FSX has obvious, even glaring defects and these products address those defects in a satisfying, affordable way. I say “address” rather than “solve” because, as the comparison with Google Earth shows, the Cloud9 landclass is not perfect.
If you want perfect, you have to do everything by hand: this is how Holger Sandmann did the landclass for Tongass Fjords, which I reviewed a few months ago and is still one of my all-time favorites. But Tongass Fjords costs about US$45, not the US$10 you pay for one of the Xclass products, and it covers a much smaller area. Xclass is inexpensive to purchase, easy to install, and makes large areas, even whole continents, look more realistic.
Also, it is getting better. Xclass: Europe has been out for a little more than one month and already there have been three updates. The most recent one uses rainfall data from last year to determine which parts of Europe should be green and which brown. Cloud9 has encouraged users to provide feedback and seems eager to incorporate that feedback in future updates to make the product more accurate. How many updates there will be and with what frequency remains to be seen; so far, the record is promising.
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