Horizon Simulations VFR USA Dallas Fort Worth

By Andrew Herd (12 November 2005)

orizon's VFR USA series of photographic sceneries came as something of a surprise, because until VFR San Francisco appeared, the US photoscenery market near enough began and ended with PC Aviator's excellent and growing stock of MegaScenery. PC Aviator have built up a strong position by showing real committment to delivering the goods over the years, upgrading their packages as successive versions of Flight Simulator have appeared and they haven't achieved such market dominance by accident. But Horizon have a similar record and it is interesting watching the two developers squaring up, my only hope being that they don't duplicate too much of their effort, because such a compromise would not only bring simmers the maximum possible number of different city phototextures, but maximize both developer's profits. However, there is some good news about the duplication which has already occurred in that for the first time, simmers have a choice about which photoscenery package to buy for a couple of major US cities: San Francisco and Dallas Fort Worth. Since we already have reviews of PC Aviator's and Horizon's San Francisco products on the site and an assessment of PC Aviator's excellent Dallas Fort Worth MegaCity scenery can be found here, read on and discover how Horizon have tackled Texas' finest before you make your buying decision.

The Horizon VFR Dallas Fort Worth package is supplied on a single DVD-ROM - note that the MegaCity equivalent is on a CD, which may make a difference for some. Installation requirements are a PC that can run FS2002/FS2004 and 1.33 Gb of free hard disk space (this is according to the manual, the box says 400 Mb) - the reason for such modest processor requirements being that what a photoscenery package does is to replace the generic 'ground' texture tiles in Flight Simulator with a digitally processed photograph of what would be seen there in real life if you had flown over that exact grid reference. In case you have started wondering how it is that anyone can charge $29.95 for doing no more than replace a set of texture tiles, bear in mind that a vast amount of programming effort goes into producing the finished result: beginning with sourcing and purchasing the original aerial photos; assembling them into a collage; cutting the collage into pieces that are the same size as Flight Simulator's landscape tiles; matching these to their correct places in FS; digitally reprocessing the new tiles to 4.75 metres per pixel; further processing to correct the colors so that they look right in FS; coding in 'seasonal behavior' so that the FS lighting effects work; adding night textures; coding supporting applets; writing a manual; and then assembling the whole thing into a presentable package with a foolproof installation that will work on four different operating systems. Nothing to it really.

Horizon's package covers 9,300 square miles in a compact oblong centered slightly to the north of Arlington, with Dallas and Fort Worth lying to either side of the midline. In addition to the phototiles, you get a new 38.2 metre elevation model, interactive water and Horizon have done us the favor of repositioning hundreds of 3D objects to make them line up with the scenery. A quick calculation reveals that, were the area covered by the scenery square, which it nearly would be if you cut off a couple of projections added to accomodate Greenville and other places of interest, it would be approximately 95 miles on a side, or three and a half hours to fly right around it at Cessna 172 cruising speed. By comparison, a climb-out at passenger jet speeds from KDFW would take you to the nearest edge in just under ten minutes, although you would be able to see the join long before you got there.

The installation is similar to all of Horizon's packages, in that it proceeds in stages with periods of apparent inactivity in between; the reason for this being that the package is divided into three interlocking areas, allowing you to opt for a partial install should you be short on disk space. The only trouble with this arrangement is that on slower systems, the delays between the installer finishing with one area and starting on the next can stretch into minutes and there is a risk that you might think the process has hung - so if at times it seems that nothing is going on, be patient! The final act of the installer is to suggest making some alterations to your computer's FS display settings, which enhance the appearance of the mesh and limit problems with texture blurring.

A quick read of the excellent manual supplied with DFW suggests that the scenery will perform best if visibility is limited to 20 nm and that 10 nm is the most realistic setting. Given that the METARS consistently give unlimited vis at KDFW, I am a little skeptical of this limit, which is more appropriate for temperate maritime climates than the clear skies of Texas, but nonetheless, lowering visibility does improve the way the scenery runs. Other tricks for improving image quality include enabling MIP mapping within Flight Simulator, anisotropic filtering in the Direct 3D options on your video card and using full screen anti-aliasing (FSAA). My personal experience is that FSAA is only helpful at resolutions of less than 1280 x 1024 and that if you enable MIP mapping, start with the slider pulled all the way over to the right and then pull it back by increments until you get a reasonable frame rate - which you can check by hitting shift-z within Flight Simulator. On my test system, which is a 3.0 Ghz Pentium, pulling the MIP mapping slider all the way over to the right almost completely cured the problem of sparkly textures in the distance and curiously, it also reduced scenery blurring to a minimum. Here, I will put in my routine note that all photographic sceneries, without exception, are prone to periodic attacks of blurring - if you want to know more about this phenomenon, please read the VFR Chicago review.

There are still some actions to be taken after the scenery has installed, particularly if you load DFW in any season except summer. Although page 20 of the manual states that it is possible to use the scenery in any season and that night lighting is not provided, this is contradicted in the Readme. The truth is that a default install of DFW only provides you with a single summer season, complete with night lighting; if you fly over the cities in spring, fall, or winter, you will see featureless gray textures wrapped over the mesh due to the lack of any appropriate seasonal tiles. The solution for the vast majority of people running Windows XP is to open the Horizon VFRUSA DFW program group, start the 'Seasons for NTFS' applet, check the spring, fall and winter season boxes and let it rip. The Seasons app exploits a little-known feature of the NTFS filing system allowing it to create hotlinks redirecting the FS scenery engine to the summer textures, the benefit being that the scenery can be seen in all seasons without any additional disk space having to be used, which is one of the few cases I can recall where I have gotten something for nothing.

FAT32 users are not in such a happy position. Limitations of the FAT32 filing system prevent the use of hotlinks and all the applet can do is to rename the summer textures to the user's chosen season, which means that FAT32 users have to exit FS and run the applet every time they want to change season - if you forget, your flight into DFW will be made over gray textures. One solution to this rather tedious problem is to use the 'Without Seasons' BGL files tucked away in the DFW folder (the readme explains exactly how to do this), the installation of which will allow you to forget about running the seasons app four times a year, but introduces a new problem in that you lose night lighting. For a fuller explanation of all why this should be so, take a look at the Chicago review, where I have gone into the issue in some detail, but my own view is that Horizon have adopted the right strategy, given that their decision allows the majority of FS users to make a very compact installation of a 'seasonal' scenery with superb night lighting under NTFS, albeit at the expense of the minority still running FAT32 having to make a choice between automatic seasonal texture changes and having night lighting. I put 'seasonal' in quotes there because in common with many sceneries of this type, only one set of photos was used to create the textures and since the photos were taken in summer, the ground tiles show summer vegetation all the year round, despite the best efforts of the FS lighting engine to make everything look autumnal.

I can hear people worrying - NTFS? FAT32? Que? If these terms mean nothing to you, Horizon have fixed things so that you can't get yourself into trouble by running the wrong app - so if for example, you try to run Seasons NTFS on a FAT32 partition, the app simply terminates without doing anything. If that happens, you need to run Seasons FAT32 and vice versa.

Although I realise that having seasons is a big issue for some people, I have always been neutral on the issue, largely because northern Europe looks much the same from the air whatever time of year it is, unless there happens to be snow on the ground. The reason why I think this was is because a large proportion of the landscape is grassland and beyond getting a little greener in spring and a little browner in summer, the view from the air hardly varies. Arable land is green in spring, browny-yellow in summer and brown in fall and winter, but there isn't so much of it that you notice the difference - and looking at Horizon's phototiles, it seems to me that this part of Texas isn't so different. The FS seasons are also highly artificial in the way they change overnight and tend to give the impression that snow is a permanent feature of winter in many parts of the world when it is not - but for seasons fans, I have changed the season in the right hand screenshot above to fall in order to show how the seasonal lighting looks. You will also notice one of the 'dreaded joins' where the photoscenery tiles yield to the default set; the reason everything matches up so well being that I also have Ultimate Terrain USA installed. I have been testing this product for a long time now - just look at the way the shorelines of the lakes in VFR Dallas Fort Worth line up with the ones in UT USA, huh? In most cases the joint is perfect and the road network joins are near enough in the same class, which is incredible, given how many of them there are.

With the photoscenery installed, Flight Simulator works just the way it always has done, with the exception that there is a longer pause than usual around the 55% mark; the moment at which the phototextures are loaded. The good news is that once this has been done, the progress bar races towards 100% and there is no subsequent performance hit, which is what you would expect, given that Flight Simulator has to load a set of ground textures anyway.

I did the testing of the photoscenery in the DreamFleet Baron, which was in late beta at the time and promising to be the best twin ever released for Flight Simulator, which has a cruise speed well suited to viewing photosceneries, allowing you to cover a good deal of ground without going so fast that you miss out on all the sights. Although the screenshots have been selected to show the different types of terrain you will be flying over should you buy the package, the pics were taken on a flight that went north from KDFW, east when I reached the edge, then south and west again back to the field. With the MIP mapping level set to eight and visibility to 30 miles I experienced hardly any blurring on a 3.0 Ghz Pentium, which is in marked contrast to the experiences I have had with lower levels of MIP mapping; Try it - I only hope it works for you.

One thing that might put some users off buying the scenery is that it completely suppresses AutoGen. Once again, there are two schools of thought on the point and I belong to the 'don't mind no AutoGen if everything else looks real enough' crowd. With phototextures as good as these, the missing AutoGen isn't obvious, especially given that the trompe de l'oeil effects generated by the shadows thrown by woods and line features on the tiles, which produce effects superior to AutoGen in many respects. One of the problems with allowing AutoGen to appear on phototexture tiles is that it is virtually impossible to ensure that houses and trees don't get out of alignment with features like roads and hedges - for my money, having houses plonked on top of the streets they are supposed to be alongside and trees slap in the middle of grazing looks plain daft, but if AutoGen is your thing, then you should consider the MegaCity package instead.

If you use the seasonal textures, you get some very snazzy night lighting, as shown in the shot above right. This was taken right at the edge of the VFR Dallas Fort Worth area and shows the contrast between the superb lighting of the seasonal textures and the anaemic lighting of the default scenery (on the right and top edges) - I had turned Ultimate Terrain off here. The other feature I haven't yet commented on is the 'Water options' app, which allows you to choose between the photoreal water that came with the original photographs, or FS2004 style 'interactive water' that can be landed on. I used the landable water, largely because the editing of the lake shores that are such a feature of this scenery is so damned near perfect that Flight Simulator's water looks just fine in them.

From a quality point of view, this package is hard to fault. Horizon's processing of the original photos is beyond criticism and they have managed to achieve very natural colors and contrast despite Flight Simulator's unforgiving lighting. One of the reasons the default landscape looks boring is the uniformity of the light, which is very flat and doesn't vary from foreground to background - in real life one of the great pleasures of VFR flight is that way light plays across the landscape and throws some areas into shadow while it bathes others in sunshine, but you don't get this in FS and it makes the panoramic views you get from 5000 feet and above look a little odd. With VFR USA DFW installed, you still have to live with this effect, but the textures are much more typical of real landscapes, thanks to the lack of repetition of the tiles.

Verdict? VFR USA Dallas Fort Worth is a superb addition to Horizon's growing American cities collection - you have to pay a little more than you do for the rival PC Aviator MegaCity package, but that five dollars grabs you double the phototexture area. For NTFS users, the decision is a no-brainer, unless you are an AutoGen fan, but simmers who are still using the FAT32 file system are faced with the choice of having seasonal and night lighting and the need to run the Seasons app four times a year, or with manually copying the 'without seasons' BGLs over and living without night lighting. Do remember that the Horizon product is on a DVD, so if you lack this kind of drive, you will need to go with the MegaCity. Otherwise, the choice is yours and we hope the two reviews help you decide - but for my money, this new Horizon package has serious appeal and it deserves its blue Armchair Aviator Award.