When will Flight Sim be like...

Well, someone is reading the blog. JasonF is apparently a big fan of Google Earth and asked: "The question that is burning on everyone's mind is when will Flight Simulator get true imagery instead of the simulated terrains that are currently shipped?". First, if your mind really is burning, seek medical help immediately! Second, have you taken a close look at Google Earth??

We actually get asked this question often in one form or another but there a few things you should think about when using one of these applications. First, the imagery you see comes from a variety of sources at different resolutions. And while all the images are georeferenced to a common datum, like WGS84, there's little additional processing that gets applied. The results are variations in color and visible seams better images from different sources. Also, wanna see what it looks like in the winter or at night? Good luck. Two mantras for Flight Sim scenery are plausibility and immersion. Vibrant green farm fields would not make sense for Wisconsin in January, thus violating plausibility, and seeing a seam running along the ouskirts of Seattle would break immersion quicker than a brick through thin ice.

The technique we use in Flight Sim is optimized to overcome these problems. To be clear, we do ship a fair amount of actual imagery--more on that below--but the bulk of our terrain rendering is used using a large (but finite) set of uniform textures that are selected at runtime based on landclass data, masked and composited before being draped on the terrain mesh. We also have seasonal variations for most of the textures so we can show you the world at any time of year. These textures are created by our super talented art team using real imagery as reference source. This technique enables us to ship the entire planet on 4 CDs--something wholly out of the question if we were to use real aerial imagery.

Now, the game engine supports custom terrain texture tiles which enables us (and third parties like MegaScenery) to render aerial or satelite imagery on the terrain. But even with that our art team still needs to process the images manually. The first step is color correction. Those photography buffs out there will appreciate the effect differences in color balance between images would have in the product. The next step is to blend the edges of the custom images into the generic textures so you don't see a hard seam. The last step is to manufacture seasonal and night variations. Not only is this a lot of work, but the cost of aquiring good imagery is significant.

So, to create a system like Google Earth we'd need (beyond the rights to use the imagery):

1. A system to match resolutions of various sources.
2. A system to automatically color-correct images to a preset baseline.
3. A system to automatically create seasonal and night variations.
4. A system to distribute the resulting terrabytes of data to a user's machine.

So, we've thought about it. Will you see it someday? Maybe. Until then, enjoy the efforts of our third parties and the work they've done. Or, check out the scenery SDK and give it a try yourself.

Comments

• Anonymous
  July 15, 2005
  Flight Simulator has an SDK?!?!?! Hmm now this is interesting. Why don't they put this with all the other SDK's. I have never heard of it, nor seen it before. Makes me wonder how many other SDK's are out there I do not know about.
• Anonymous
  April 19, 2006
  Speaking of the FS SDK...has anyone in the FS blog realm talked about what we can expect from FSX's SDK?
  
  I tried my hand at programming C gauges once the Panels  FS2004 SDK was released but got a nose-bleed trying to fathom what was happening behind all those pesky macros that the SDK seemed to be made up of. I wasn't a big fan of the gauge drawing engine apparently being purely GDI/GDI+ either :)
  
  Looking through the FS2004 SDK header files was also a nightmare with barely a comment to be seen. All those lessons in programming I've been exposed to evangelise about properly commenting your source files to aid other programmers who use your code. Yet here was the FS2004 SDK seemingly shunning this sensible advice with minimal comments. Things were made all the more difficult due to the SDK documentation being quite sparse in its explanations and even examples on how to get things done. This left me with the impression that the SDK was somewhat of an 'afterthought'.
  
  There's been a great shift lately in opening up game engines to not only commercial third-party support but also to the fan-base (Half Life, Unreal, Oblivion etc). Add-ons are one of the primary reasons why Flight Simulator has been so successful these past 20-odd years so it would be great if the creation of the FSX SDK is part and parcel of the continuing design and development stages rather than a quite poorly documented  afterthought.