In X-Plane 11, the new lighting and material model, which uses Physically Based Rendering, is always on. Even at the lowest settings!

In X-Plane 9, 10 and 11, we have introduced major changes to the lighting model at new versions, so we could have a reasonably stable lighting environment for the life of the product. Each time we introduce these new features, we need to decide if they are always on or optional.

My preference is “always on” when possible; having these kinds of big features be optional makes life difficult for authors, who can’t be sure how their content will look in the simulator.

When we introduced HDR with global night lighting in X-Plane 10, it was (and still is) an optional feature. This is because deferred rendering mode uses a lot of GPU memory bandwidth, and many Intel GPUs simply can’t handle this rendering load. Because Intel GPUs represent a non-trivial percent of our install base, we can’t make features that don’t run on Intel hardware mandatory. Thus HDR remains optional. (We checked this in X-Plane 11 and we still can’t make HDR mandatory. Maybe in X-Plane 12. 🙂

The new lighting model ties three features together: (improved) volumetric fog, atmospheric scattering, and physically based lighting equations with the new material model. These features are always on in X-Plane 11, and this makes life easier for our artists; the lighting environment is always the same no matter what the settings.*

With physically based rendering, we support lower end systems by reducing the quality of the effects, rather than by removing the effect entirely. Most of the cost of PBR is in calculating the processed reflection textures to make PBR work. At low settings we can reduce the texture resolution and remove detail.

This tuning is still in progress; testers who were in our private beta program know this because they saw significantly worse framerate in beta 1 than in the public beta. A lot of this performance tuning is finding ways to make the lower end settings do less work than the high-end settings.

I’ll post more next week on how to use the new PBR rendering, but for now this is posted and a good start.

* It makes life easier for me too by greatly reducing the number of combinations to debug.

About Ben Supnik

Ben is a software engineer who works on X-Plane; he spends most of his days drinking coffee and swearing at the computer -- sometimes at the same time.

68 comments on “Physically Based Rendering Is Always On

  1. Is it possible to increase how often the reflection on the aircrafts updates? Seems to be locked at ~5 FPS, which makes it look unrealistic.

    1. It is, but as of now it’s pretty performance prohibitive. I am hoping to get some blending into the reflection calculation which would make it look a lot less jumpy.

      1. I assumed it was part of the bug that caused the flicker in the water reflections as well. I turned the setting to lowest to get rid of it and it made it look nicer. Better to reflect something inaccurate than to have your attention drawn to bad movement.

        What is calculated for the reflection? A cubemap around the plane?

  2. Surely we need some adjustment of the gamma Ben? It just looks so all whitewashed out. At some angles a white based aircraft just blends completely into the background. Doesn’t look realistic to me.

    Have you also locked off the troublesome traffic volumes?

    Interface is genius, very well done….

    1. No gamma adjustment. Gamma adjustment isn’t going to fix tone mapping or fog issues. It’s just going to completely screw up the original colors of everyone’s liveries.

      1. is the bloom around sun at low angles a bug? if not it needs to be dialed waaay back

        also where will we see the next build and how often will you guys push builds wile in beta?

          1. its been a 2 weeks now when will we see a new build?

            also what happend to the new GPS/G1000 and other new Aircraft?

            also can we get the XP10 water back the new water looks awful i hope thats just place holder

    2. Adjust your monitor/TV settings. X-Plane 11 is amazingly real in it’s lighting and I base that on 4 years on the flight line working on jets and also as a pilot.

      1. Yes I did just that! straight after posting (sorry Ben) and it is better, but the monitor is now quite dark for normal use?

        So you have to adjust the monitor to XP11 and not XP11 to the monitor… SD

        1. Lightning and haze is stunning in X-Plane 11. I just pushed all my Photo Scenery over Denmark From X-Plane 10 and It is simply stunning how real it looks.

          Great Work LR Team…

      2. Agreed. Felt that from flight #1. The new lighting and physics based atmospherics are so different from a “gaming” experience that one might think something is amiss. Made me feel like I was back in a real plane again. Once the clouds are tweaked to match, the “willing suspension of disbelief” will be much easier to attain, and immersion an order of magnitude better than X-Plane 10.

  3. A great achievement Ben & LR folks !
    I think many users with average systems were delighted and somewhat surprised that V11b could run at a workable pace and with a reasonable helping of the excellent new effects .Even my 2008 Mac Pro/ 1GB card was hanging in there with a few clouds to boot (KESA was a bit more of a struggle ) . A smoother transition than V9 to V10 and if we’ve lost some finer control tools in exchange for a more universaly consistent performance in V11 than thats no bad thing.A tad hazy some might say but reading posts across the org for many myself included it ‘feels’ more like flying , being in the air.Which is fantastic ! A few boring bits about hat switches etc on their way..

    1. I thought my iMac 21.5″ with 512 MB Vram was “average”. It will fly the Cessna 172 but nothing else at the moment. (see my earlier post for some fps). I’m afraid I am going to have to be satisfied with V.10 as it looks as though my “average” is LR’s below spec!

      1. If you have an iMac that can run x-plane with 512 MB of VRAM, the -best- case is that you have an Nvidia GTX 660M – you might even have a 640M or an older AMD-based iMac.

        So…by the standard of modern flight sim machines, gaming machines, and 3-d graphics, your machine is definitely in the bottom tier of hardware. X-Plane runs well on a GeForce 680 GTX (at 1080p – it probably struggles at 1440p) but the mobile GPUs from the iMacs are significantly cut down from that.

  4. Really loving the light interactions in the new engine.

    You mentioned improved atmospheric scattering, but I’m not sure I can actually see it in sim at the moment. At a basic level, mountains in the distance don’t seem to be any bluer, just greyer. Am I missing something or are these effects on their way?

    When they do arrive, will they be able to respond to different volumes of fog / haze / times of day? The RTH hacks for XP10 tend to look great for one set of environment conditions, but then not so good as the time of day / atmosphere changes.

  5. Hi Ben.

    It will be awesome if the PBR thing gets the optimization for the low end systems, it looks terrific. I am also looking at an EGpu for my laptop.

    I am not sure if this should be posted here or filed as a bug report, I downloaded the tiles for the South Pacific and areas are missing like Sydney . some parts of Queensland. Was it left out intentionally like the north part of Alaska ?


    1. Those are bugs, some known. I think something went wrong in the render. Sydney seems to go haywire every time around in some way.

      Basically if it’s below 60N, file it.

      1. will do so along with refiling of the control surfaces bug as i am not sure if it has reached , thanks for the reply.


  6. It’s amazing how good it looks X-Plane 11 so far. I’m really trying to fly a normal flight sadly I can’t make it happen due some massive frames drop which develops after a certain time. But I ain’t giving up hope and keep trying and, checking for patches/updates, speaking of which. Are there any small patches/updates coming along so far? I assume not everyone has those massive frames drop and for those who said, I did remeber them strongly say “it is not optimized yet” which seems logical for a beta ofcourse.

  7. Hi Ben,

    Can we use NORMAL_METALNESS in .ter files as well ? More generally
    if BASE_TEX, BORDER_TEX and NORMAL_TEX are used at the same time
    what should be the order between the border and normal_map couples of
    data planes ? (I mean border (s,t) is 8,9 and normal_map is 10,11 or the inverse ?)
    Also, can we only fill the blue and alpha channels of the normal map (and just rely on data planes 4 and 5 for normal orientation) ?

    Thanks !

    (I strongly support those who think that the lighting model is greatly improved now !
    My only minor criticism would be a slightly exaggerated (yellow) color shift at dawn, which turns better again once at dusk.)

    1. Hi Dider,

      NORMAL_METALNESS is not yet available in scenery but will be soon.

      UV data planes are always albedo UV then borders. Normal maps always follow the main UV for albedo. If you use an RGBA normal map you have to put -something- into R and G, “128” isa good neutral value. We may introduce a 2-channel normal map format in the future to save VRAM that would give you just metalness and roughness.

      1. Perfect, looking forward to experiment with it then, no hurry !
        VRAM will not be an issue if we are allowed to assign coordinates into it on a per vertex basis, I’ll probably only use a small square 2D gradient (one direction for each channel) as a normal_map texture.

  8. Something odd I have experienced with XP11, which seems counter-intuitive and can’t justify; but then again I am not too familiar as to how PBR works in that regards.

    I experience significant reduction in FPS (from 35-40 to 10-15) when zooming in close to the texture (say the side of the stock C172 fuselage). I mean really close.

    Where’s on XP10, FPS would significantly increase when zooming very close to the texture. I was sort of attributing the increase in FPS, with the reduction of visible objects the GPU had to render, thus allowing higher framerate when zoomed in.

    1. The PBR shader doesn’t have performance that scales with distance. The night HDR lights do slow down when zoomed in and speed up when zooming out WRT fill rate.

      1. Thanks Ben. I experience this behaviour in daylight. Is this a bug that I should report or is it WAD?

        My system, with pretty much maxed out settings, exception being 4x FXAA + SSAA
        4790K OC’d to 4.5GHz
        Nvidia 1080 8G

      1. Well zoom will always drop fps a little: when we zoom we draw less scenery (horizontally) in more detail (with more LOD so you see more than a blur zoomed in). The problem is: the scenery comes in big GPU sized chunks so even if you zoom in we might draw the -entire- airport terminal anyway (for example). So the LOD increase from zooing raises the work load but the smaller view angle (from zooming) gets very little perf back.

  9. I was pleasantly surprised that my 2010 Mac Pro AMD 5870 can “kinda” run x-plane 11 with decent settings / when the settings are turned way down, its still pretty slick.

    If I can find the cash to, would love to throw together a gamer box with an OC’d i7 and an nvidia 1080 for x-plane.

    I think x-plane 11 hits that goal that x-plane 10 didn’t quite: make a photorealistic sim that can kick the heck out of all current hardware, but grow as new hardware comes out.

    Someday i’ll be able to max out the settings, turn on shadows for everything, crank AA, and it will be *awesome*

    1. Definitely not. Unfortunately the BLEND_GLASS directive requires that the participating geometry be part of the post-HDR alpha pass, which only the aircraft have access to right now.

      If we someday provide post-HDR glass in scenery, then this will be straight forward to implement – it’s not a crazy thing to add to the scenery system.

  10. I know this doesn’t pertain to the discussion here but how is going with the “Final bug fix for XP 10…..” There is one bug we are still tracking: a number of professional customers have reported worse external-visual tracking with 10.51 than with 10.45. If you see this on your setup, please file a bug; we are working with these pro customers individually to test possible fixes.”

    Just curious if XP 10 is done.
    Thanks Mark

    1. We sent out a private test build and it was considered better than 10.51 but didn’t beat 1045 for all customers, so we’re going to tke one more look.

  11. X-plane 11 looks terrific although my AMD card is having trouble in fps. Do you have any plans to adopt Vulkan in anytime?

    1. Vulkan is on our long term road map – we do want to adopt the new APIs. Not sure if it will help your AMD card, it depends on the issue. I see 30 fps on my HD7970 with moderately high settings.

      1. Befuddling. On my MSI 7970 OC Edition + Crimson 16.11, the demo of XP11 (fresh install, no plugin, no add-on) can barely reach 12 fps, and that’s with *all* options turned down and (for good measure) resolution at 720p.

        1. I don’t know why this is happening but I am not totally surprised; Mike Brown of XForcePC reported terrible fps on the R390 – he sent one to me and it worked fine. I think there’s some kind of setting or property on the AMD drivers that we haven’t found yet that must be killing things.

          1. @Ben: I have also terrible frames on an amd card, in this case the RX 480 on all graphic-settings. So your presumption about the drivers could be right. Hopefully you will find a solution soon, so we can also enjoy the beta and can help to support the development. At the moment it isnt really possible because of the low frames.

            By the way. X-Plane 11 looks really great 🙂

  12. When you place a current 10.51 Aircraft into the new XP11 Simulator, most of the buttons and knobs appear as yellow edged boxes and almost all of the pannel instruments are considerably darkened to the point where many features are unreadable. Will most aircraft from xp 10.51 have to be modified in order to be used in XP11?

  13. The shadows on the 747 panel are very dark and make the panel unreadable even at noon in summer. Can this be lightened somehow or even turned off?

  14. Hi Ben,

    I need some information about sunrays which are not implemented , i have no graphics knowledge but would it be a part of the PBR at a later date ? or is it a different thing altogether ? like a shader effect or some ?



  15. hey Ben,

    you mentioned in a previous post that the v11 water would be much better, had a video, but that Mac would be a long time way. well, whatever was done to the water for now, it looks much better than v9 v10, so thanks

  16. I get the old FMS and GPS warning.
    But when I go to replace it all I find is units that say for 3D only.
    I do not like the 3D panels, it just seems unnatural to me. I really like 2D better.
    And I do not know how to build 3D panels, and would not like it when it is done anway.

    After moving in many old aircraft with the old GPS and FMS the planes load just fine.
    It seems like they still work! Am I dreaming or isn that for real and ok.
    Does the software engine that runs those two instruments still work correctly

    If one is building an aircraft from around 1985-1990, the old FMS and GPS look correct for the period.

    And yes what you have done is a remarkable improvement.

    My only real problem is locating where my favorite things are.

    1. 1. Legacy aircraft with legacy FMS -will- work (if not resaved) as long as they didn’t have a G430 and FMS on the same “side” of the aircraft.
      2. Once you re-save you have to go to modern instruments.
      3. If you like 2-d, use the popup floating instruments.

  17. I am assuming that the development and bug repair work in and on XPlane 10 is going to continue for some time to come .. at least in 64 bit mode. Scenery development using XP11 looks like a huge problem because of its current operational status. I am planning to do my scenery design in XP10.51+++ awaiting its achieving much improved operation for developers and users alike. Please verify that scenery design will transfer over to XP 11 without changes and that new scenery objects and functions will be placed in both versions of the simulator.

    1. Hi Bob,

      No. We are -not- going to do additional development of X-Plane 10. The only scheduled X-Plane 10 update is a 10.52 with an improvement in smoothness for multi-machine networked setups.

      You can continue to develop scenery packs in 10.51 and open run them in X-Plane 11, as long as you are not doing anything that’s been deprecated. You’d be crazy to be doing that even if you were targeting v10. The look of 11 is clearly different though, so for example if you are creating your own textures, v10 is not a good proxy for how things will look in v11.

      For example, in v11, the OBJ 2.0 format from x-plane 6 has FINALLY been dropped! On the scenery side there isn’t much else that’s removed.

      For lighting, the main danger is that if you “hack” your v11 textures (E.g. intentionally desaturate them) to make them look better, the desaturation will look overdone in v11 since you don’t need to do that in v11.

      1. Just to comment on this.

        I simply did symlink of my own airports (I actually did it for all my cuspom scenery from XP10) directly from XP10 to XP11 and it runs perfectly and it looks stunning. I do see some buildings that I need to correct some coloring but that was my intention anyway.

        I’ve released a video ( where I use all my old XP10 custom scenery in XP11pb1 and it have never looked that good!

      2. However you drop X-Plane support for 10.5x, you will need to make the scenery upgrades and their corrections to it for some time in the future. I assume that you will be doing this, because right now XP11 can’t even set and store the pitch and roll settings for my MadCatz F.L.Y 5 Stick that is sold by the X-Plane Store. So using XP11 doesn’t even present me an operational version for checking. ( The bugs are submitted). People who a developing scenery and updating old scenery packs have already done a great amount of beneficial work for you. A new version in alpha state is not the Taxi-Path and Runway Flow verifier tool we need for scenery development — you already have just struggled to make XP 10 an excellent performer for this purpose. Let us use it,please.

        1. Hi Bob,

          We are not going to port any new v11 developer tools that are inside x-plane 11 back into X-plane 10. These tools are part of the entirely new code for v11 and cannot be ported back.

          You can continue to use v10 for development as is, and continue to use WED. V10 hasn’t gone away – but we are not adding yet more stuff to it.


  18. Hi Ben , I have a question related to the aircraft lights and the x-plane default lights.
    I see that in XP11 some lights reflects in the aircraft objects and some not. The aircraft lights don’t, no Beacon, Strobe , Nav. Is that some thing that we must be doing in properties ? Or will this lights have any new reflection effect in the aircraft ? Will default aircraft lights affect the objects ?

    1. They should reflect – I’d have to see the specific combinations of lights, rendering settings, etc. There are still a few missing shader paths.

      If a lighting effect USED to work in 10 and is now GONE in 11, please file a bug ASAP – the sim should only be doing more.

  19. Hi, thanks for the answer and your time, I mean in a non HDR render setting , the Beacon, Navigation, Tail , Strobes has no effect in the plane object , only in the scenery for the (Land lights). My question is not related to a bug. I wonder if this lights will reflect in the plane objects or will be like the XP 10, that it don’t. Will the XP11 be featured by this lighting reflections, LR have any plan for it ?

    1. The non-landing lights have -never- thrown spill in non-HDR mode – not in v9, not in v10, and not in v11.

      We may someday be able to add suport for multiple landing light spills without HDR in v11, but that is not in 11.0.

      If you see spill on an aircraft from these with HDR off, it means the artist painted it into the fuselage, e.g. that’s how the P180 was done in v10.

  20. Why are rendering setting options so basic? Turning off useless features (for high altitude or IFR flyers) like road traffic and ocean reflections, I can squeeze out a few more frames to use for other settings.

    I can get better frames with more autogen on XP10.

    Also, why does it perform terribly on medium settinhs on a 6700k and a GTX 1080? I’m getting 42-55FPS, and lower with certain weather settings. Please don’t impose dumbed down options settings – it seems like you’re trying to appeal to Apple’s idea of simplicity.

    I’ve been an X-Plane flyer since 7.63, and am worried about the perfomance issues. On X-Plane 10, when I updated my GTX 970 to the 1080, I saw ZERO FPS improvement, and I’m not alone in having this problem, it is easily recreated. How on earth is this properly optimized? I will be making a video on this to bring the performance lies to light.

    1. If you’re getting 42-55 fps with a 970, I am not surprised that you saw no improvement with the 1080 – you’re probably limited on the CPU and not the GPU, and therefore using a bigger GPU just means more idle GPU resources.

      I’ll write up a separate post on rendering settings as soon as I can; there’s logic behind the changes, but I need to focus on getting public beta 2 bug fixes out first before I can spend the needed time to write something coherent on the subject.

      1. Thanks alot for the reply! Sorry if I sounded critical, but X-Plane is very dear to me and has a special place in my heart…

        You’re right, I just did a rough over clock to 4.7Ghz and there os a slight improvement in FPS… Is there anything I can do to help even more? I’m just surprised by the amount of CPU power needed 🙁

        1. Probably not – you’re already pushing the envelope of how much CPU power you’re making available. Further improvements (especially to get up into the 60 fps range at higher settings) have to come from perf improvements on our side – more optimal code in our engine, use of newer graphics APIs, and better parallel processing -within- the frame. X-Plane does a decent job of putting loading on the second core and sometimes gets some work per frame on other cores, but making both work together without limiting fps is tricky.

  21. I don’t know how difficult it would be, but I was wondering if you would ever consider using something such as Truesky for the clouds and sky. Someone on the .org contacted them and they responded saying, “Thanks very much for your message. We’d be happy to support a project to create an x-plane integration or plugin for trueSKY, though we don’t have the manpower free to do this internally just now. If you or anyone you know is interested, do let me know.”
    Their website is here:

  22. Any plans on finally replacing the default Runway/taxiway/asphalt textures with 2k x 2k (or 4k x 4k DDSs) and finally rid ourselves of the old ones which look like they were made for X-Plane 6? 😉

    Since many of the Terrain .DDS textures in XP10/Xp11 are 2k x 2k (and most aircraft are now doing 4k x 4k textures), isn’t it time to update these “stock” textures to say, at least 512 x 512? 😉 With a “low”texture setting in the XP11 “texture resolution” prefs, these would look alot better if people have to “dial down” the VRAM settings. They don’t lose out on a blurry runway when theyre close-to-the-ground

    There’s no library entry for them, so there’s no developer-friendly way to replace these textures liek we can with a .POL (and possibly add things like normals/UV to change the shinyness when viewed at glancing angles, or add a decal to them to simulate horizonta grooves like most runways have now for rain dissipation..).

    I’m sure some of the freeware developers who’ve developed their own replacement textures (FlyJSim, MisterX6, Sabach, etc..) are more than happy to “Let Laminar have these” to use in XP11 gratis — If only to make the “stock” software much more visually appealing to the new users. (Nothing like seeing the same blurry/ugly runways weve been using since X-Plane 8 runways when you load.. ugh..)

    – CK.

    1. The runways are due for an upgrade. I’m hoping to not just increase the texture res; the runways are so close to the aircraft that we could use insane amounts of VRAM and still have them only look “okay” up close. In the meantime, that giant chunk of VRAM would be costing us on final approach and a bunch of other flight conditions. (Very modern GPU cars can do GPU memory paging to help alleviate this cost but that’s a complicated and heavy handed solution that not every user can use to the problem of “we just burned VRAM like cigarette paper.”)

      With v10 we started applying high frequency noise textures on top of lower res daytime textures, with interaction between the two layers for added detail; this kind of thing could work well for runways and let us get more detail while recycling some of the higher res components. It’s crazy to have to have 36 copies of a high res texture so that big blocky numbers can get swapped out, for example.

      We’ve also talked internally about using some of the new shading to make the apron pavement better. The runways could use an upgrade but the aprons are really unrealistic – they’re just massive expanses of repeating tile, and there’s only so much you can do with patchworks of polygons and some decals. Real aprons have an arbitrarily complex mess of oil stains, rubber marks, paint, cracks, patches, and natural variation in the look of the materials that break up the view – I’d say right now the aprons are the biggest “tell” that you’re looking at a computer image among everything on the ground. (Well, that weird bug where the trees become mirrors is a bit of a tell too. 🙂

      Finally, there’s one rendering tool that I think we’re missing – it’s been on my wish list for the low level engine for a while: a draped polygon with “edging” on it. Right now if you put a draped polygon down in the sim, the edge is sharp, and the author has to manually wrap something around the edge to smooth the transition, e.g. you can put taxi lines around the edge of your pavement. Sometimes this is automated (e..g the road files have the edges built-in) or easy (you can pick an edge line for a WED taxiway polygon) but it has to be done by something every time and it’s repetitive and wastes GPU memory. I’d like to be able to apply a repeating polygon of material (with low and high frequency effects running on top to add detail and break up repetition) and get the kind of nice, soft, “chopped” edge we get in other parts of our engine, but automatically.

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