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Introduction to Flight Simulator

Microsoft Flight Simulator 10 (FSX) is the latest in a long line of flight simulation programs released by Microsoft and is one of many flight simulation programs on the market. At its most basic, a flight simulator is a computer program which simulates flight. That is: reactions to inputs and decisions in a real aircraft are replicated as closely as possible by inputs and decisions in the simulator.

As well as the more obvious components of a flightsim, such as the models of various aircraft, the way they 'fly' and their many complex engine and avionic systems, a successful flight simulator needs to have something to fly across (and occasionally fly on!)- In other words, it needs to simulate Earth.

Like any type of simulation, the environment through which you move is a very important part of feeling like you are 'really there'- If things don't look the way your mind would expect, it is less able to be tricked into believing that what you are seeing on screen is reality. Some flight sims have concentrated on a small part of the globe so the developers can re-create that area in greater detail. Microsoft Flight Simulator 10, the flightsim for which the VectorLandClass addon is designed renders the whole earth! Over 24000 airports all over the world!

Given that the task of rendering the whole globe is a very difficult one, it is no surprise that some parts of the world have received more attention than others... sadly, the representation of New Zealand in the default FSX data isn't befitting of a country of such unique beauty.

Luckily, Microsoft designed FSX in such a way that addon developers could create software packages to enhance most aspects of the simulator from aircraft to weather and clouds to airports and, of relevance to this document, scenery.

This is where Vector Land Class comes in.

By converting some of the best geographical data representing New Zealand into the formats required for FSX to understand and display, VLC enhances what the user flies across and makes a simulation feel that much more real.

However, even a small country like New Zealand is still a very big place! So how did the VLC team go about re-creating this beautiful country in FSX?

We started with generating a base landclass layer using GIS analysis, taking into account various data sources, geographical algorithms and old fashioned manual tweaking ...but that didn't satisfy us because it wasn't accurate enough to represent the many small changes to vegetation that New Zealand experiences. In order to get around this we developed a revolutionary approach to displaying landclass information which displays landclass areas as vector polygons.....These are much more accurate and can display landclass boundaries accurate down to a few meters.

We added roads and tracks and water polygons and coastlines and streams and developed custom GIS tools to attribute and split the data into tiles for optimum performance. We also developed tools to place 3D models of things such as Radio masts and Marae all around the country.

We then complemented this highly accurate landclass with custom ground and autogen textures and gave the user control of all these features with a configuration tool built specifically for us.

But how does FSX then use this data? A quick summary is below. If you want a more technical background to the FSX terrain system, download the FSX terrain white paper here

Firstly, FSX examines any addon scenery folders for data that covers the area that the user is intending to fly across. If any data is found, it is loaded depending on type.

To avoid duplication and conflicts, VLC contains files that exclude the underlying default data. Excludes can remove any type of scenery information- We choose which parts we want to keep, and which we want to get rid of.

FSX then starts to load any 'mesh' information to create a virtual 3D model of the terrain. That information is presented as the hills and valleys that the user flies across, varying from the non-descript to some of New Zealand's most majestic physical features such as Mount Cook or Milford Sound. VLC includes a replacement mesh where each pixel is around 20m in size, or around 4 times the accuracy of the default data!

FSX will then load landclass, seasons and waterclass files (VLC includes upgraded versions of all of these) and from those determine which textures should be draped over the mesh model. A landclass representing pine forest will load and drape a texture onto the terrain under that polygon generated from aerial photography of actual pine forest. However, it isn't that simple: Each ground texture is actually a large set of texture variants with a subset being picked depending on the season, water type and time of day. The simulator engine will also process the scene further so that our pine forest texture will automatically change to, say, a rock texture in very steep country and shade it according to sun angle.

At this stage, the user would be flying over a virtual world with textured hills and valleys giving a good representation of reality if looking directly downward. However, when a user is flying, most information is presented obliquely so the world can appear very 2-dimensional if the terrain isn't populated with other 3D objects such as houses and trees. For this reason each texture links to various models of trees and buildings which match the land type. So our pine forest polygon will be populated with 3D models of pine trees placed on top giving the appearance of a proper forest....and remember each of these autogen textures need to have correct day/night/season variations too!

Whew. So, so far we have a selection of objects with different textures placed on a selection of textures with variations placed on terrain placed on a virtual model of the globe. Quite an undertaking!....but your poor processors' job isn't finished yet.

Our scene wouldn't be complete without roads, tracks and railways so these are also draped on the mesh ensuring that each line modifies the underline mesh model so the road is 'flat' across. As well as roads, railways and tracks, VLC includes 'Freeway' information which adds moving traffic to certain roads.

No flight in New Zealand could be carried out without seeing at least one area of water, so these need to be rendered and shaded depending on their 'class' (i.e. muddy, clean, shallow, deep etc) as well as having a shoreline drawn around them. Smaller water bodies such as streams are then also draped on the mesh. To top it off VLC also adds custom objects to the scene such as lights and buildings and the sim renders the atmosphere including the sun and stars, clouds, rain, snow and fog. The result is an immensely immersive environment over which the user can pilot their virtual aircraft.

You can start to see why FSX brings even the most powerful of computers to its knees....and we haven't even started talking about aircraft, airports, AI aircraft......

Are you learning to fly in real life? Read on to see how VectorLandClass and FSX can help!

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New to flight simulation and want a better understanding of what it is and how this addon package works? Read on!

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