I can see clearly now...

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I recently went to the optometrist to get my prescription updated, and if you have glasses or contacts, I'm sure you've gone through the little dance: "Okay... which is better, the first one? or... the second one?" as he or she flips through various lens strengths until you find your sweet spot.

The new version of Flight Simulator is going through the same sort of thing, as far as our terrain system goes. Since this is an area near and dear to my heart, I'm happy get a new prescription, so to speak.

In the coverage of Flight Simulator X seen in the February 2006 PC Gamer magazine they mention a 16X increase in terrain detail. Where does that number come from? And what does it mean?

Well, in previous versions of Flight Simulator (like the current version Flight Simulator 2004) we used 256 pixel X 256 pixel sized squares that cover roughly 1 kilometer square area of space. That represents a resolution of roughly 5 meters per pixel.

From altitude that's not so bad.

It looks a bit like this from a hundred meters or so:

5 meters per pixel (256 X 256 textures)

If we move it up a notch and use a 512 pixel X 512 pixel image to represent the same 1 KM of space we see a lot more resolution:

2 meters per pixel (512 X 512 textures)

By going all the way up to a 1024 X 1024 image we get 16 X the resolution (16 256 X 256 images fit into one 1024 X 1024 image):

1 meter per pixel (1024 X 1024 textures)


So which would you choose, number 1, number 2, or number 3?

Not sure?

Why not take a look at all three in this link (~500k file) :


  • I think 1024*1024 is memory overkill, if you don't imply level-of-detail techniques.
    In case you did imply LoD, you have to worry how to make the transition from one resolution-level to another resolution-level smooth.

    My personal favorite is to have 512*512 for terrain, and one 4096*4096 for the nearest airport, so one could even bake ground-markings into the terrain-texture. As a side-effect, this would allow sloped runways more easily.

  • Andreas,

    Hmm. I can't say I agree.

    Seeing the difference in action, well, it's the difference between wearing glasses and not wearing glasses.

    The slope work you're doing looks like it's coming along nicely.



  • Well, I was talking from the point-of-view of a GPU.

    Of course you can't argue against the fact, that 16 times the resolution looks 16 times better.

    Maybe I was just a little bit jealous ;).

  • >My personal favorite is to have 512*512 for >terrain, and one 4096*4096 for the nearest >airport, so one could even bake ground->markings into the terrain-texture. As a side->effect, this would allow sloped runways more >easily.
    I'd settle for 1024x1024 at the nearest airport. 2 meter default and 1 meter res at airports seems logical for this release. The question is however, what increase in mesh resolution will we be seeing to compliment the texture increase?

  • Sure, it looks better but it's still a bit like flying over a giant postcard isn't it? I often expect a 500 acre post stamp to come into view... ;)This is not really criticism of course, I think you guys are doing a terrific job.

    But I was wondering: could terrain texturing be done entirely through procedural shaders? You could go smoothly from 50k feet down to individual grass leaves...

    Heh, it's probably a bit early for that :)


  • Oh, #3 for sure!! I'm anxious to see how this has been (or being) done for all of the many landclasses!! Great work, J!!


  • Agree with Gerard.

    When flying low, the faster your plane goes, the less detail/more blurry the ground details will be. However when going very slow at low altitude, there should be some predetermined/analysed mapping to decide what type of procedural grass and such to add there and then tax of CPU/GPU can be kept at bay by having the detail only at max when the plane stands still or there is a lot of spare processing power left.

  • The stripes in (fields) and the color of together with the size of the area of the aerial images could be used to decide whether there's a field, forest or plain etc there, and in large non-city areas, if you try land of some road that information could be used to use mostly in-GPU done weed or trees in such area. Certainly it would not match the real life look exactly, but much better than just a flat blurry texture that most flight games have had (or the few trees in place of a forest).

  • go for the 1m resulotion for the terraintextures. remember this sim is to be around also 3 years in the future from now. dont worry about memory. the highter res you can make the terrain-engine paint the textures - the better. I love your work !!!

  • Yeah, 1m/pixel!
    The detailed textures of autogen buildings and trees blend in much better with the ground surface, making for a much more natural look!

    The higher detail in the autogen textures actually emphasised the less detailed ground textures in FS9...

    Thanks for showing us,
    Martijn Pleines

  • HI Jason,

    Excellent, more details, I think it will be more easier as well.

    For those don't like 1m 1024x0124 I think there is should be a way to resize your texture to lower reso, like we can reduce the texture, never limiting a terrain engine, especialy when new singlr Msfs version is here from 2 to 3 years.


  • Jim:
    "The question is however, what increase in mesh resolution will we be seeing to compliment the texture increase? "

    Can't say. Expect some change.

    "I was wondering: could terrain texturing be done entirely through procedural shaders? You could go smoothly from 50k feet down to individual grass leaves... "

    Truthfully? There's no inherent reason we couldn't use procedural texture genaration. That being said, I have yet to see a demonstration (and I've seen a bunch), that I thought would serve as a total end to end solution. Generally proceduarl terrain looks great for moors, and grasses and the like. Cities, farms, and other manmade stuff *I* think leaves alot to be desired.

    I believe (and this is just my opinion here) that the future doesn't lay in increased texture resolution, but rather in increased 3D res: Rather than making the flat have more pixels, lets see more *vertical* polygons...

    Doing that gets us both blades of grass at some point... :)

  • This looks fantastic, no more big green blocks representing trees :> ! This will make flying VFR that much more realistic :). Add this to the herds of animals that are supposedly going to wander the ground, the cars and trucks driving down the roads, and of course the birds filling the skies; FSX is going to be a GA simmers dream come true :>

  • Jason, there is some work being done in Germany - the Lenne3D project. In terms of landscape visualisation this is the best I've seen in a real-time environment, pretty impressive stuff:


  • Christian:

    Great link! thanks.
    Looking at screens like those from the site you mentioned:
    illustrate what I'm talking about with regards to 2D resolution versus 3D density.

    While it may not seem like it, there's a *lot* of overlap between our two products...



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