• Scenery and HD Mesh v2: Q&A With Andras Fabian (alpilotx)


    tonywob

    Andras Fabian, also known as alpilotx is a well-known developer in the X-Plane world. Andras, as well as working on the default global scenery inside X-Plane 10, is also responsible for the incredible HD Mesh, Tree Lines and Farms and New Zealand Pro.


    Luckily, I've managed to grab Andras away for a short while to ask him a few questions about his work, and also to clear up some common misconceptions and questions about the various scenery available. I also encourage everyone to visit Andras's website, and have a look through the gallery and articles posted there.


    image.jpg

    Can you tell us briefly about what you do for Laminar Research?

    It's already quite a long time since I started to contribute to the Laminar team. It started many years ago during the XP8 run, when the world was quite empty, and not even forests were in it, but at least Ben Supnik has already added the technology for rendering forests ... well, at that time I started adding those forests to the scenery, and released them as - free - add-ons for Europe and the USA. This project was then extended to X-Plane 9, which already had some rudimentary forests, but they were not very accurate (and we could do better).

    At that time - X-Plane 9 - I realized, that the main reason for not so good forests, and a not so accurate landclass representation was that Laminar did not have good enough raw data to start with (better, free data really only became available somewhere around the first days of XP9). So I approached Ben Supnik, and asked if I could try to improve this. Luckily we already had a quite good working relationship at that point (through all my forest efforts), so he agreed and helped me a lot to get started.

    So, thats how things started. Then I have spent approximately 3 years with completely overhauling the raw data and processing rule system for XP10, which finally resulted in the default Global Scenery which ships with XP10.

    But I need to add at least two more names here, because the Global Scenery was not solely my work. There is Alex Gifford, who is the mastermind behind all urban things (urban transformation rules, complex autogen definitions and all the autogen artwork are all his baby), and also Albert Laubi, a very long time friend from Switzerland (we worked together on all the forest projects), who is "my" artist, and supplied me with gazillions of textures, terrain definitions (which defines how textures are applied and which shader tricks they use) and many ideas on the way to the Global Scenery (he has a very good knowledge of geography / geology and has seen lots of places on earth, so he always had great ideas and observations to share).

    Starting with HD Mesh, how does the HD Mesh differ from the default global scenery? What is included inside the HD Mesh?

    Well, first of all, the HD Mesh Scenery (currently v2) is NOT a photoscenery (which many users tend to misunderstand)! It is effectively the "big brother" of the default Global Scenery (shipping with X-Plane 10), and as such, it is - how should I call it - a scenery, which gains its visual appeal from employing a large set of generic textures based on landcover / landclass information (gained from a multitude of real world data sources).

    image.jpg

    One of its big pluses compared to the default Global Scenery is - as its name suggests - the much higher density of its triangle mesh (about 2-3 times denser, which by the way is an irregular triangle mesh). This is very positive in at least two ways:

    First of all, it of course allows a much better representation of the underlying elevation raster data (a more detailed triangle mesh can represent much more elevation "points", much more accurately)

    Secondly, this also allows a much more accurate and detailed representation of the underlying landclass data! In X-Plane 10, the landclass information is - kind of - coupled with each triangle (or better, triangle patches) of the mesh. Thus, the more detailed the triangle mesh is, the more detailed the landclass data can be represented. Depending on the resolution of the source landclass data, this can be irrelevant or very important .... And indeed - at the moment - at least for Europe / North America / New Zealand and Japan the raw data is really detailed (even more detailed than the current HD Mesh Scenery v2 resolution is most of the time - yes, because the irregular triangle mesh has some denser and less dense areas ... within some configured limits)

    But, the HD Mesh Scenery v2 is much, much more than just a base triangle mesh (this is basically the same as with the default Global Scenery - just with lots of newer data). In X-Plane, the base mesh is effectively a combined data set of the base mesh (with its landclass information "bound" to it), water bodies, forest area polygons, autogen zoning information and all the vector data (like road, railroads, power lines). So, here is the list of improvements (over the default Global Scenery) which I just take from my website (in addition to the first two main points above!):

    • It is based on a completely new Openstreetmap (OSM) data (from approximately the end of September 2013), which brings (compared to default Global Scenery - its OSM data was from mid 2011) a lot of improvements in:
      • Water features (lakes, rivers, coastline) – many previously missing water features are now finally there
      • Roads
      • Railroads
      • Power lines
      • Urban park areas
    • It includes line rivers from OSM (not just polygons as before) tagged waterway=river which improves the landscape in most regions quite a bit
    • Uses improved urban zoning (thanks to improved algorithms in the scenery generator)
    • Many smaller and larger landclass data improvements:
      • Completely replaced the landclass data for Canada (big improvements)
      • Improved forest density representation in Europe (changed the sparse / dense classification)
      • Some new classes added (in many regions), like: moraines, riverbeds, mining/dump sites
      • Added differentiation between ice (perennial) and snow (more temporal) to have an even more detailed representation of mountains. There is a nice description of this by Albert (the texture master) on x-plane.org: follow this link
      • Added differentiation between irrigated / non-irrigated crops (in some regions – like the USA etc.)
    • Completely replaced the elevation data with viewfinderpanoramas.org (if yew have a few cents, donate to that guy!). This doesn’t change much in areas which were already great, but fixes some which were really hosed.
    • Latest airport data (2013.10) boundaries used, to have up to date airport areas.

    Does HD Mesh Scenery v2 contain buildings and forests from OpenStreetMap (OSM)?

    No, HD Mesh Scenery v2 (just like the default Global Scenery) does not include this type of information from OSM! The main reason is, that with its more global approach it needs to use data, which is available globally (whereas landclass / forest / building information in OSM is extremely varying with regions - some are fantastic, others are empty). That's why it uses the autogen approach, where urbanized areas are "approximated" with informations from landclass data (and generic / autogen objects are placed in those areas).

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    It's the same with forests. They are not derived from OSM forests (again, because they are in many areas completely missing) but are approximated from the landcover raw data. Depending on the raw data and the "simplification" by the scenery tool, the (larger) forests are still usually quite accurate (especially with HD Mesh Scenery v2). You usually only miss out on the very fine details or smaller forest stands (you will notice this difference when using highly accurate photoscenery).

    How often is the HD Mesh and X-Plane's global scenery updated?

    Currently I only had two versions of the HD mesh Scenery v2, but at least I have some ideas to maybe re-cut it yearly. This is not a final decision, neither cast in stone, but I think, that somewhere this autumn, it might be worth to release a new version. With fresh OSM data (so, people, don’t stop mapping!), bug fixes (yes, there is already a list of "known issues" on my website - most of them "fixed" internally) and other improvements which might come over the year (just a few days ago I experimented with more accurate forests in Europe etc.).

    I also plan to add new regions when good enough data becomes available (this is very important for those, who always ask, when I will do this or that region: it all depends on the availability of free, high quality raw data!!). At the moment, I have Japan in the pipeline, which might see a release over the coming months.

    Which regions does the HD Mesh cover?

    At the moment I have covered Europe and most of North America (+ Hawaii), and with a little luck I might also extend the coverage to Japan.

    How does it effect performance?

    This is a complex question. First of all, as it seems, the FPS hit is not very big ... almost neglectable (at least many users have confirmed this). Of course, as with other scenery, the more "stuff" it shows, the lower the FPS goes, so usually cities are on the lower-end and, while the wilderness is usually much faster (but where you have extensive forest coverage, that can hit FPS too - a bit).

    What is maybe more important is the memory hunger. Of course, the HD Mesh Scenery v2 needs more RAM than the default Global Scenery (of course, it has much more data in it :-) ). So, as of X-Plane 10.25 I highly recommend people to have at least 8 GB of RAM (which only works with X-Plane 10 64-bit!) to have a smooth flying experience. Also, with the upcoming - and announced - X-Plane 10.30, this will become even more critical. X-Plane 10.30 has a new feature, which allows much longer visibility (no blurry textures at high altitude etc.), but this feature comes at a cost. It needs to load twice the amount of scenery files to cover the long distance .... and this also means a doubling of RAM requirements. So, if you want to use HD Mesh Scenery v2, and want long range visibility, be warned! You better plan on having 16 GB of RAM, otherwise you might get nasty problems with swapping ... and with OSM (World2Xplane) scenery on top, even 16 GB might not be enough (it also depends on the region you fly in - but the more detail it has, the more data it has).

    But the good news with X-Plane 10.30 is, that at least, FPS is almost not hit, even with long range visibility (as far away, X-Plane draws much less of the data - only the textured mesh), and it also has a switch to turn off long range visibility, thus bringing you back to "normal" RAM usage just like it was with 10.25!

    What did you improve in the second version of the mesh?

    I think, this is more or less answered with my list of improvements. The reason is, that v1 had absolutely no new / different data than the default Global Scenery. With v1, I really only upped the triangle mesh density, but with v2, there is a big list of improvements (see above)

    Does HD Mesh change regionally

    Oh yes, and this is a feature which is identical with the Global Scenery (this one I didn’t change / improve for HD Mesh). We use a quite detailed climate model (from real climate data at quite high resolution, telling us mean annual rainfall and temperature) to make the scenery look more - uhm - regionalized. We cover climates from cold to hot trough dry and wet (in a multitude of combination). They are represented in many different terrain definitions (TER files - you can see them in "Resources/default scenery/1000 world terrain/terrain10/"), which also point to the right texture (which change with all these climates). This of course makes the entire scenery and terrain diversity quite complex.

    Additionally - to make things even more complicated :-), we have also mixed in some information about red/non-red rock formations (on a global level), or about irrigation / agricultural patterns.

    Finally, to make things even more complex, we also have a few, special regionalizations which are mapped in via the library system. Thats why there are a few more terain10_XXX folders in ""Resources/default scenery/1000 world terrain".

    Oh, and of course, just like the terrain itself, the forests react to the climate information equally. This means, that for example a broad-leaved forest has a lot of variants for all different "climate zones" :-), Thus, a broad leaved forest looks different in Norway than in South Italy, and yes, indeed - as my previous example shows - we do differentiate between broad leaved, coniferous, mixed forests, and also shrubs or orchards .... this is all thanks to the mostly quite detailed landcover raw data we use to generate the scenery.

    Where does the data come from to generate the scenery, and how do you get everything working together so nicely

    Oh, this is a quite long list (but you might have already guessed that after my explanations above, how this or that part of the scenery falls in place). The good thing is, that I do already have this list added to my website Data Sources / Acknowledgments

    Does the HD Mesh work with other scenery?

    Yes, quite well to my knowledge, and usually there is no reason for it not to work. But it's very important - and I emphasize this - that people do (pretty please!!!) conform to the short installation instructions on my website. Especially having the correct order of scenery in the scenery_packs.ini!, and it's also important to correctly add the Earth nav data" folder :-) !

    http://www.alpilotx.net/downloads/x-plane-10-hd-scenery-mesh-v2/#Installation

    What are the differences between HD Mesh Scenery v2 and SimHeaven.com photoscenery?

    There still seems to be a great amount of confusion about the similarities / differences between the two scenery projects and when, how, and which one should or can be used:

    • HD Mesh Scenery v2 (is what we we're talking about here)
    • HDv2-based DSF for photo sceneries is what Simheaven offers

    So, I wanted to make some points clear here, because the former is NOT the latter, and the latter is NOT the former (while they still share a lot)!

    As the name already suggests, "HDv2-based DSF for photo sceneries" is based on the HD Mesh Scenery v2 (so, HD Mesh Scenery v2 is the source from which the photo scenery is derived!), and because of this, they are identical in many ways:

    • They have exactly the same road, railroad, power line data (which comes from OSM)
    • They have exactly the same water features like lakes, rivers, coastline (which is derived from OSM too)
    • They have exactly the same autogen information (which is based on a mixture of 3rd party landclass data + OSM roads / railroads)
    • They have exactly the same forest data (which in HD Mesh Scenery v2 is based on the landclass data, as described above and not from OSM!)

    The ONLY big – but important – DIFFERENCE is:

    HD Mesh Scenery v2 shows you generic textures (the same set which comes with X-Plane 10.25/10.30) which are placed / spread out based on very detailed landclass data (see my descriptions on this topic above), whereas HDv2-based DSF for photo sceneries shows you photo textures usually derived from Google maps via the tool g2xpl!.

    There is a second, less know difference because of the way how textures are applied. The tool "slighty" re-cuts the irregular triangle mesh structure of HD Mesh Scenery v2 into rectangular patches, so it can apply the rectangular photo texture tiles onto those small rectangular triangle patches. Because of this – the changed triangle mesh structure – "HDv2-based dsf for photo sceneries" can sometimes have a little bit different elevation representation (usually only seen in mountainous areas with a lot of fine grained changes in elevation data).

    After all, this also has another important implication! Because both sceneries have a base triangle mesh included (a base mesh), they can only be used in X-Plane 10 exclusively! They can’t be mixed (for very good technical reasons)! If you have more than one of them (and the default Global Scenery counts too) installed in the same place, then X-Plane 10 will only show you the one with the highest priority in the scenery_packs.ini! , the other one(s) will just sit on your disk and take up place (but there are no other problems to be encountered)!

    So, in the end its quite easy. You have to decide if you rather would like to see photo textures or if you are much more happy with the (intricate, complex and usually good looking) generic texturing approach. Everything else is – usually – similar in both sceneries!

    New Zealand Pro

    The next scenery we'll discuss is New Zealand Pro, which offers a high definition mesh scenery for New Zealand, a beautiful but often neglected area of the world in flight simulation.

    What made you decide to create a separate scenery for New Zealand?

    Well, the main reason for New Zealand was data! As I pointed out above with HD Mesh, my work is always dependent on free, quality data sources, and New Zealand was/is very special in that it has a fantastic free data source, which far surpasses almost everything else I know. With that data, I had a long standing dream to bring it to X-plane ... which also needed some unique solutions, even some artwork additions (which I don’t do too often, as I am not the best artist) and other tricks.

    Technically, NZ Pro is very similar to HD Mesh Scenery v2 ... just with a lot of nice extra overlay data, like real world data based tree lines, gazillions of single building objects spread across the landscape, and some more special single objects (light houses etc. - those objects were my few own artwork creations, done with Blender) .... all thanks to fantastic source data.

    What data sources did you use for New Zealand?

    Its called LINZ!

    Is there any conflict if I have both NZ Pro and HD Mesh installed together?

    No, absolutely not, as neither of them covers the other's region, they do not collide in any way. So you not only can, but should have them side-by-side.

    Does NZ Pro work with other scenery?

    Yes, to my knowledge it works quite nicely with other NZ scenery packs. I have quite a few of them installed. I can highly recommend the additions from ISDG for example!

    Tree Lines and Farms

    The final scenery we'll discuss is Tree Lines and Farms v2

    In brief, what does Tree Lines and Farms do?

    The "Tree Lines and Farms v2" scenery is a typical eye-candy scenery, which you can just add in, and get some nice extras (well, tree lines and farms that is - what else of course :-) ). Of course, it's best enjoyed in combination with HD Mesh Scenery v2 (but it is completely independent from it, and will also nicely work with default Global Scenery or any other photo scenery!)

    How does the scenery know where to place the trees and farms?

    It is kind of an "artificial" scenery which gets its data through some heuristics and algorithms, but it's still based on hints from Openstreetmap data (so it's definitely not entirely made up)! So, how does it work?

    Tree lines are generated along all OSM-based roads, railroads, rivers and lakes via some randomization. The algorithm also checks (using the same data as I already have for HD Mesh Scenery v2 / Global Scenery) if the landclass type is some open land (usually agriculture, grass) and only then does it add the tree lines, and it factors in climate data, so the tree lines get the same climate dependent forest definitions as the other forests around them have. Additionally, the algorithm tries to avoid airports (no one likes trees on airports :-) ) and clears roads for inadvertently placed tree lines.

    Farms are similarly placed heuristically. Here the algorithm checks for short, open ended roads ("antennas") in the OSM data, and if they end on grass or agriculture, then with some randomization, it places a farm object (again one of my few own artwork creations).

    Does this work with HD Mesh v2 and other scenery

    Yes, it works very well with other scenery. Its just very important, that you ALWAYS place it above any base mesh type scenery (Global Scenery, HD Mesh Scenery v2 or any photoscenery)! Otherwise you will not see it.

    Another problem can be, that objects (the trees or farms) can in some rare cases collide with other scenery (like airports) ... in those cases it's best to have some well-placed object and forest exclusions in the scenery (which anyway is highly recommended and good practice for any airport)

    Tony: I'd just like to add here that the tree lines provided by World2XPlane are different than the ones provided by Tree Lines and Farms. The tree lines inside World2XPlane follow the farms and river banks exactly as depicted and tagged solely in OSM, with a density dependent on the settings used to generate the scenery. Andras’s Tree Lines and Farms uses some clever algorithms to place trees and farms, as described above by Andras. Both sceneries can be used together, but please make sure Tree Lines and Farms is placed above any World2XPlane/Simheaven scenery, otherwise it won’t work.

    What can we expect future wise from the global scenery and HD Mesh?

    Well, I can’t say too much for the Global Scenery, as the decisions / planning for that are usually on Laminar's side. I just provide them with all the newest data, processing rule improvements, algorithm improvements etc.. etc... but they decide when to re-cut anything based on it.

    For the HD Mesh Scenery - as I hinted above - I think I might do some kind of yearly re-cut ... Though, I can’t promise it for many years in the future, so who knows, but at least I hope to do a re-cut sometime this autumn (2014) again ... (but no guarantees here).

    Also there are little HD Mesh additions like Japan in the pipeline.

    I'd like to thank Andras for taking the time to answer questions and talk about his work and scenery for X-Plane 10. If you haven't already, head over to alpilotx.net, and have a read through the information there and screenshots. I'm sure you'll be impressed with his work, and the difference it will make inside X-Plane.



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