Difference between Textures, Mesh, Terrain, Landclass, etc?

[Guest squale]

I see there are all these different add-on programs from FS9 that deal with different types of scenery, I don't really understand what each scenery item actually is...I am going to most likely get Active Sky 6 (it comes with Active Sky Graphics), and also probably get the Flight1 Ultimate Terrain USA.I also was thinking of maybe getting the Megascenery USA 2004so now will all these programs overwrite each others scenery? or does each program do a different TYPE of scenery... I guess I really don't understand all of this and I don't want to spend money on stuff I can't utilize at the same time...I also don't want to kill my FS9 performance, so if one add-on does everything very good, then I will just go with that one..

[John_Cillis 2,406]

Here's a quick replyMesh= The scenery data that controls the height of the terrainLandclass= The scenery data that controls the type of terrain (i.e. farmland, forest, city, etc...)Waterclass= The scenery data that controls the shading of water.Terrain Texture = The visual bitmap used for each type of landclassAlso, there are:Cloud texturesEnvironment textures (controls things like the color of haze, the hue of clouds, the hue of the sky. My Soft Horizons add-on in the file library is one example of how environment textures can be used)Add-on static scenery (Airports, buildings, vehicles, etc)Road add-ons such as USA RoadsAnd I am probably missing some, but this should make it easier to understand when you're shopping for scenery add-ons what the add-on is for.-John

[Guest squale]

so is there any scenery package that can do these all?how is the Flight Ultimate Terrain USA?

[Guest imoz]

I bought the Flight 1 Ultimate Terrain last week. I really like it, with a few caveats. The night lighting at night is really cool. There were only a couple of things I noticed that you should be aware of:- I have a pretty beefy machine (Athlon 64 X2 dual core, 2GB ram, 7800GT video card), and Ultimate Terrain still gave me a noticeable hit. After playing around with some tweaks I was able to get it back to a nice state, but just be aware that it is loading ALL of the roads etc. so its a lot of data.- Ultimate Terrain is highly accurate, and as a result a lot of the default FS2004 objects wind up misplaced. There is a guy with an add-on scenery package that works really well and re-locates these misplaces objects/bridges/statue of liberty etc. to where they are supposed to be. The project homepage is http://www.qlrp4ut.com/ and I believe the guy posts on here too.With the QLRP4UT + UT package I have been really pleased. Especially night time approaches into a big city in the Concorde!Here are some night time screenshots I took (dial up warning - they are 1920x1080):http:// img395.imageshack.us/my.php?image=nighttimedepartingkabe1lp.jpghttp:// img395.imageshack.us/my.php?image=chicago0me.jpghttp:// img395.imageshack.us/my.php?image=kennedytakeoff4ts.jpgAnyway, I don't think you will be disappointed with Ultimate Terrain.EDIT: I put a space in the hyperlinks between the http:// and the rest of the URL, because the forum was auto-generating IMG tags and trying to hot link gigantic images :-) I will try to figure out how to post them linked with thumbnails later.

[meccadom 1]

John, thanks for your post.Can you please rank them generically in order of placement (loading) in the scenery cfg from top to bottom, ie highest priority (smallest rank number)to lowest (largest rank number)?in other words, does mesh sit on landclass which sits on terrain, which sits on textures, etc.ThanksDom

[RobdeVries 28]

textureslandclassmeshterrainRob "Holland&Holland" de Vries http://www.emotipad.com/emoticons/Flying.gif"To go up, pull the stick back. To go down, pull the stick back harder"

[Guest DK8290]

"textureslandclassmeshterrain"What is the "terrain" you refer to in your list? As far as I'm concerned there is only mesh as the base of all FS landscapes, textures on top of that are placed according to the landclass file's directions. Specific addon "scenery" like airports sit on top of it all. My list would be;Addon sceneriesLandclass3D MeshGround textures are placed by the landclass's directions and so in the list they are associated with the landclass. Please explain what you refer to by the word "terrain" in your list.Thanks ---------------------------here's my explanation of how I see these things3d mesh ... like a huge grid of points with x and y coordinates and an elevation data for that point. Computer creates land-shape surface over all these points to make the basic FS world shapesground textures .... bitmap images placed in various ways onto this 3d mesh to give the impression of various land types (fields, city, rock, snow etc).landclass ..... is a file of data that instructs the sim where and what ground texturing to place . FS default one can be inaccurate and even miss whole towns and cities. You can download freeware ones or payware ones.scenery" ... is a word I take to mean a product which can combine several of these things but is a more accurate representation of a smaller specific location like an airport or a city or area of land. They can have a more detailed 3d mesh for that area, photorealistic terrain textures and a specific landclass to the area as well as custom-made buildings and airport objects.There are products that combine more detailed mesh for a large area (the world even) and have replacement textures and landclass too. I'm not sure if I'd call this type of product 'scenery' though.I always think of the word 'scenery' in FS as a specific area.I think some words can get into a grey area in this case and maybe we need a new word LOL.I don't think I'd label Ultimate Terrain in any catagory. It's road and railroad data, coastal shape and bodies of water data, some urban landclass, and a night-lighting feature. It doesn't contain any 3d mesh data or ground textures.

[RobdeVries 28]

VTP polygon thingies by which accurate coastlines etc are made of?Rob "Holland&Holland" de Vries http://www.emotipad.com/emoticons/Flying.gif"To go up, pull the stick back. To go down, pull the stick back harder"

[Guest DK8290]

WHat's VTP stand for.I thought the coastal shapes was part of mesh somehow. Then again Ultimate Terrain has that and I doubt it would alter existing 3d mesh. So these data are a separate file than the mesh files? wow .... always something to learn ;-)

[RobdeVries 28]

Look at the scenerydesign forum here for VTP and Richard Ludowise. There's -plenty- information on this subject :)Or take a look at the Terrain SDK from Microsoft: The Terrain SDK explains how to add new line and polygonal data such as roads, rivers and coastlines. Which in my opionion defines the terrain. But i'm just a humble simmer ;)Best!Rob "Holland&Holland" de Vries http://www.emotipad.com/emoticons/Flying.gif"To go up, pull the stick back. To go down, pull the stick back harder"

[LuisFelizTirado 33]

It's really not that complicated, and you have all got the idea.1. altitude mesh - this is the elevation, or the relief, of the ground, that is, hills, mountains, valleys. There are different resolutions to the altitude mesh - for example, some have spacing of 76 metres between elevation points (this is LOD 9) while some of the default mesh has spacing of 600 metres between elevation points (LOD 6). Obviously, the higher resolution mesh (with smaller spacing between points) provides the more realistic altitude mesh, but at the cost of lower frame rates.2. Land classification, or land class - many write "landclass" but this is not correct. It is all due to the fact that Burkhard Renk came out with the first land class modification tool about 5 years ago, a commercial product. Since he is German, and since Germans tend to link words to form longer ones, he wrote "landclass", but this would not be that correct in English, although it too is essentially a Germanic language. Since then, just about everyone, even in Redmond, has written "landclass"! Anyway, land class is a file that indicates where to place the different types of ground textures (forest, field, urban, rock, dirt, ice, etc.) over the altitude mesh. Mostly, the default land class does not reflect how the world really looks. This is due to the fact that there is no accurate, world-wide, land use data base, so the FS Team had to go with what they could get, which is mostly wrong. But, there is plenty of replacement land class available (although much of it is also not very realistic), and, most of all, it is very easy to change the land class - see John Cillis' LandClass Assistant, in the Avsim library.3. Water class - this is the same as land class, but for water. There is a variety of different water textures: deep sea, shallow sea, inland water, different tropical water, etc.4. Land and Water Masks (L/WM) - basically, this redoes the land and water masses to more closely resemble reality. For example, new coastlines (a run-on word in English, how strange!) are made with Water Masks that replace the default. They are simply polygons, either of land or water, that display over the default.5. VTP (Vector-based textured polygons) - roads, rivers, shorelines (another run-on word!), streams are examples of VTP scenery, as are most of the default bridges! (Shorelines, by the way, only refers to beaches, not to coasts that are LWM.) They are essentially lines that are used to display a texture (or an object, in the case of bridges), whether of a road, or a beach, or a stream, etc.VTP is also used to display large textures on the ground, for example, golf courses or parks, forests, etc.While the altitude mesh would seem to be the foundation, the basis on which everything else is "draped", it may not be quite so obvious for the rest. FS 2002, and FS 2004 after, took a different approach to putting together the terrain. No longer are there layers of elements, with one on top of the other. Instead, all the elements - land class, Land and Water Masks, VTP - are integrated to create a single and unique ground tile that is then laid over the mesh. And even the mesh can be modified by a LWM flatten, a polygon whose only role is to modify the mesh. But, all this is not really important to the user, except for the fact that this technique has substantially improved frame rates.This is essentially the lot, all the terrain elements that go into creating the ground in Flight Simulator.Different scenery packages may combine various elements in order to offer a better representation of the world.Best regards.Luis

[scott967 62]

Good recomendation. Also, the first topic in the scenery design forum is a good starter. From my view, I try to separate scenery into three subsets:Terrain3d ObjectsEnvironmentTerrain consists of textured polygons covering 1.2 km squares over the surface of the earth. Several different elements are combined (in a specific order) to create the final terrain which is drawn to the screen. Some of these elements are independent of each other, some are layered. A complete terrain definition requires providing the polygons (shapes) and the textures (colors) needed to create the final result.Polygons:Mesh is a source of polygons which reflect surface elevations. A key point is that mesh is raster data -- a regular grid (by lat/long) of elevation data which FS uses to create polygons. The default FS provides mesh in different resolutions (distance between points on the grid) for the whole earth. In general, highest resolution is used when available and "in view".VTP/LWM are terms which reflect a second source of polygon data. These polygons are vector data -- the corners are defined and FS draws lines between the corners to create the polygon (here, lines can be considered as thin polygons if the polygon is not "closed"). VTP/LWM are more complex, in that they can define textures to be drawn within the polygon, as well as the polygon itself. VTP/LWM can be defined to conform to whatever mesh is active within their areas, or to change the mesh. The common way they change mesh is to "flatten" areas within the polygon, either to provide a base for 3d scenery (such as airport scenery), or to provide a "sunken" appearance for streams or roads. These VTP/LWM polygons can overlay each other. FS provides a layer scheme (not visible to the user) to define which polygon is drawn first, and hence "covered up" by other polygons in the same area. FS also provides a means to exclude and replace polygons. The scenery area priority (scenery.cfg) determines which polygons will be excluded and replaced.Once the terrain polygon model has been created by combining the above elements, it is necessary to apply bitmaps (textures) to them.Textures:Like mesh, there is a global texturing system called landclass/waterclass. These elements are files which define textures which are applied to all the polygons within 1.2 km squares. Each texture is 256x256 at its highest level of detail, hence, the best resolution obtainable is about 1.2/256 or 4.8m. Landclass and waterclass textures are grouped by land cover type (or water depth), global region, season, and day/night. When both landclass and waterclass definitions exist for an area, the landclass will be drawn. Note that the complete landclass/waterclass requires both the definitional files and the actual texture files they define. The default install uses single global files for landclass and waterclass. Note that while the whole earth surface has waterclass textures defined this is not true for landclass. Hence to create "ground" where it doesn't exist in the default you MUST provide a land texture definition (either addon landclass or VTP/LWM polygon with land texture). It is possible to replace the landclass and waterclass textures within any 1.2 km square with a specific "photoreal" texture (with possibility of seasonal and night variations). These textures also prevent any textures defined by VTP/LWM from being used within the square (except for a so-called alpha channel, which will allow waterclass texture to show). Photoreal files also use a definitional file and actual texture files and the defaults are contained within the "scenery" folder structure, under the "cities" folder for specific areas FS has provided. Once the basic landclass/waterclass texture is drawn, any VTP/LWM polygons are textured, using bitmaps defined in the polygon definition. An important variety of these polygons is the mask polygon, which simply determines which texture, the landclass or waterclass will be shown. Typically, this is used to override the default behaviour of landclass textures showing where both landclass and waterclass are defined. A configuration file is provided, terrain.cfg, which helps determine which specific texture is used for a VTP poly (for example, 2 lane dirt road or 4 lane concrete road).The default scenery has VTP/LWM polygon definitions in files grouped by area and type. Note that this scenery does not use the "XML" definitions introduced for objects in FS9. The first two letters provide the type, and the following 6 numbers the area. The default files with AP, BR, NV, and OB are not terrain, but 3d object placement files. Default files not conforming to this are generally 3d object definition library files. A complicating factor is that FS provides a means by which 3d objects can be defined for texture bitmaps, without having to explicitly define the world coordinates for the object. These objects are termed "autogen". Positioning of these objects within a texture bitmap is defined by an annotation file, and the actual object created is defined by configuration files, default.xml and terrain.cfg. Within the terrain system, these objects can be excluded by defining VTP polygons using textures without autogen defined. They can also be excluded using 3d object exclusion methods not discussed here.Note that there is much more done by FS before drawing the terrain defined by this system on screen. Textures are blended at their edges, eye viewpoint is defined so that hidden polygons are removed (such as reverse side of hills), perspective applied, and lighting/visibility/shadow/shading applied. Animation effects such as waves are applied and complexity sliders from fs9.cfg applied.scott s..