Hi all,Could somebody explain in laymans terms the difference between the various types of file that go into making the FS2004 experience.I understand MESH files form the shape of the terrain (I also understand the basics of LOD classification) and also that the textures are essentially graphic files that sit on top of the MESH terrain.However, can somebody explain AFCADS, Landclass files etc and what I need to put on my system to get the best experience?I do a mixture of GA VFR and Jet (Airbus A320 mainly) flying around Europe and am pretty new to FS in general.Cheers, Kris

I like to divide it as such:AircraftEnvironment/weatherObjectsTerrainAirport facility dataThe distinction is that different tools and files are used in creating these categories.Keep in mind that the basic problem for the graphics engine of the program is twofold:compute the appropriate geometry for all objects in view and convert these into a 2d representation for each frame of the scenecompute an appropriate color for each visible pixel in the frame.There is in additon a physics engine, which determines how the aircraft and aircraft systems interact with the various scenery classes, and to a lesser extent, how the environment interacts with other classes.Putting these ideas together, we could consider as an example:Create an object by defining its gemoetry and its colors. There are various tools and techniques used for doing this. I recommend reading the top thread in the scenery design forum for insight into the process. In many cases, the nature of an addon is defined by the type of tool used in creating the geometry and coloring.Addons typically address the problem in two ways:They might provide a single class of scenery over a large area, such as terrain mesh or landclassThe might provide all, or many at least, classes of scenery in a limited area such as an airport.It isn't always clear when you consider an addon just what it will cover, though there are some conventions that have been developed over time. There is an additional concern in that FS has typically allowed for backward compatability of designs from the previous 2 versions of the sim. The earlier designs still work, but they don't always coexist as well as one would like with the current version designs.Here is an example from your question: AFCAD.AFCAD is a type of scenery created using the AFCAD 2.2.1 tool. Its goal is to modify some scenery classes within the area of a single airport. AFCAD modifes certain airport objects (runways, taxiways, aprons) using predefined gemoetry and colors. It also modifies airport facility data, (communitions, AI aircraft behaviour) which impact aircraft physics. scott s..

Hello Kris,You know altitude mesh, it is just the relief, the elevation points of the ground.Land class assigns the ground textures that cover the relief.Water class modifies the water color - deep ocean, coastal, tropical, etc.AFCAD modifies the default airport layout (runways, taxiways, aprons), but generally does not change approaches.The more you add to your FS installation, the greater the resources that are needed to display everything, but do not hesitate to do so, until you are tired of bad frame rates.Best regards.Luis