Glossary of Terms

Glossary of Terms

3DS File-A 3D Studio file as well as having the basic model information can also contain texture mapping information and information on what texture is applied to what face(s). This is not directly importable by OPTech but a utility called 3DSOPZ can convert these into the OPZ files OPTech uses.

AlliED- An excellent XWA mission editing/creation package which is more user-friendly and as capable as those used by TG to create the XWA missions.

Boolean Operations- Boolean logic is the basis of computer programming and can also be used in the modifications of pairs of meshes in some 3D modelling packages. There are four types of operation that I know of:
Subtraction (A-B)- In this case where mesh B overlaps mesh A a hole the shape of this overlap will be created in mesh A. This is useful for cutting recesses such as hangar wells or where the shape of a mesh will be changing abruptly.
Subtraction (B-A)- This is the same as the above but the hole will be created in mesh B.
Intersection- Rather than a hole the shape of the overlap being created in one mesh in this case the result is a mesh of the shape of this overlap.
Union- In this case the two meshes will be combined into as single mesh which will have any intersecting faces trimmed so that the outer "skin" of the mesh is one continuous piece. This is very useful for the purpose of eradicating intersections by temporarily or permanently combining meshes and therefore avoiding edge-wobble and venetian-blind effects.

Bump Map- In many 3D modelling packages and some art packages it is possible to define how the height of a surface varies by using the same method as used on landscape maps of having higher points marked with lighter colours and lower points with darker. Although XWAs engine does not support bump-mapping it is possible to fake this by using a bump-map to define thing such as panel lines or minor dents/bumps and rendering these onto the texture. These should be used with care as if you have use a large setting for their effect on a fairly small map the detail can have jagged edges and also the stronger the effect the more contrast there could be between this and the lighting in XWA.

CBM File- A graphics file format which XWA uses to contain both still pictures such as the medals and short simple animations such as the doors opening and closing on the main concourse. XWA can automatically generate CBM files from either BMP (for stills) or FLC (for animations) files.

Collapse- What you do after an all night session trying to make a modification for XWA. Also the term used in 3DS MAX for combining things together, whether it is collapsing two or more vertices into a single vertex, one or more faces into a point, a mesh with a set of modifiers applied to it into the end result (so that rather than having a mesh with a taper modifier you just have the tapered mesh), or a group of meshes into a single mesh.
One thing to note about the last example is that you can either collapse the meshes together using Boolean operations, which will modify the meshes as mentioned in that section, or they can be collapsed together without the meshes being modified which can more be useful in some situations.

DAT File- Literally just a file containing DATa, which in XWA editing is generally graphical data for things such as the Skirmish mode pictures, hull icons, and the main concourse. Other graphical data is contained in CBM and SNM files.

DXF File- The most basic (as far as I know) sort of 3D model file containing the model information but not anything such as texture-mapping coordinates, what texture goes where, etc.

Edge Wobble- XWA has to calculate where any intersecting faces "join" many times a second and these calculations can vary slightly and therefore so can the line of the "join" which can look like it is wobbling about.

Extrude- A rather useful tool in 3DS MAX which lets you select a face or faces and then either extrude them outwards into a bump (positive value), inwards into a dent (negative value), or to create some almost coplanar faces (very small value) which can be shrunk before these are turned into a bump or dent.

Face Normals- When a face on a 3D model is defined (whether by 3 vertices or by 4) it also needs to be defined from which side this face will be visible from and from which side it will be invisible. An imaginary line at right angles to (also known as at a normal to) the plane of the face is drawn to show this.

Frame- In 3D animation this refers to a single picture of the hundreds that will make up the complete animation.

Flightgroup- In mission editing/creating this is a group of ships which have been created and are being treated as a single object. These ships will be of the same type, same AI level, share the same orders, and share the name of the flightgroup plus a number.

Global Group- Sometimes in mission editing you may want to group different flightgroups together so that a condition or another flightgroups orders will apply to this group as a whole.

Global Unit- Same as Global Group but with the added feature that the number at the end of the flightgroup name will relate to that ships position in the Global Unit rather than the individual flightgroup. This is quite useful for fighter squadrons where you may want to create 3 flightgroups of 4 (and define them as a Global Unit so you would have 1 to 12 rather than 3 lots of 1-4) rather than making a single flightgroup of 12.

Hardpoints- These are used to define the coordinates for things such as weapons, hangar entry points, and docking points and to define what sort of thing it is at those coordinates.

Hitzones- Every computer game involving 3D models has to calculate whether this model has been hit by something and for this purpose hitzones are used. In XWA the reaction of the particular mesh to being hit (whether it is individually destroyable or not), how it is labelled in the target list (both for the player and for AI craft given an order to attack a particular component), and other things such as if it will rotate are also defined by the hitzone type.

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Keyframe- This is a frame where the animator has defined a position or the start/finish of an effect rather than being one of the intermediate frames which will be created by the 3D animation package between these keyframes.

Level-of-Detail- At longer distances less detail of a model can be seen in a game and so less needs to be shown. It is possible to define lower detailed parts of a model and the distance at which these will be used, or for smaller details simply a distance at which they will vanish, so that the load on the players computer is reduced and so the chances that XWA will become jerky.

Material ID- If a Multi/Sub-Object material has been applied to a mesh then the Material ID number defines which of the sub textures is used. This can also be used to "bookmark" the faces of a mesh when combing meshes with Boolean Union so that they can more easily be selected after the meshes have been combined.

Mesh- Every 3D model is made up of one or more meshes (sometimes known as objects) which are the component parts. Each mesh is made up of the vertices and faces that make up that part of the model and can be moved and manipulated as a single entity as well as modified by selecting individual faces or vertices.

Multi/Sub-Object Material- If more than one texture needs to be applied to a mesh then rather than using a Standard material a Multi/Sub-Object material can be used. This material consists of two or more (I am not sure what the upper limit is, but 10 or 15 have been used) materials each of which can have a different texture.

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OBJ Files- A 3D model format that can include texture mapping information and be imported by OPTech. This does not include information on what textures are applied to what face however so this has to be redefined in OPTech.

OPT Files- These are the 3D model files used by XWA for ships and objects within the game and which contain information on things such as weapons locations and how different parts of the model will behave.

OPTech- An excellent OPT creation package which can be used to add the game specific information to a 3D model so that it can be used as an OPT.

OPZ files- The OPTech project format.

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Shading/Smoothing- When two faces join at an angle rather than having an abrupt change in the way they are lit this join is smoothed over so that it is a more gradual change. This is a fairly common practice in 3D modelling (/animation) to make rounded parts look rounder and to make corners look less razor sharp and therefore more realistic. XWA applies a strong smoothing effect to the OPT files which means that for things which are meant to be round relatively few faces are needed to make them appear this way. However this also means that if you are trying to make a mesh with a faceted appearance (i.e. with quite sharp joins) then you run the risk of the edges being smoothed over too much.
The strength of the smooth effect can also account create extra shading on some more complex models which has to be solved by preventing face or groups of faces from affecting each other.

Smooth Groups- One way to prevent XWA from adding extra unwanted shading when the new version of 3DSOPZ is released will be to set up smooth groups. These are used to define what joins between faces should be smoothed across and which should be rendered as a corner by separating faces into these different groups.

SNM Files- The proprietary animation format that TG used for XWA for the cutscenes and some of the larger more complex animations. This file format has not been decoded as it was judged simpler to create a new Dynamic-Link-Library (DLL) which would intercept XWA calling its SNM player and instead play an AVI file if one of the correct name was present.

Textures- These are the pictures which are applied across the surface of a 3D model to give it more detail, colour, and (as the name suggests) texture.

Triangle Asymmetry- When vertices are moved within a relatively low facecount model it is possible that although the vertices may be symmetrical that the model may not appear that way because the "diagonals" between vertices on both sides of the model will slope the same way ( |\|\| or |/|/| ) rather than these being mirror images of each other ( |/|\| or |\|/| ) as well. This is solvable by chopping the model in half, mirror-copying it, and then joining the two halves together.

Triangling-to-Infinity- If a mesh has too many faces (the point at which this becomes true varies greatly) then it can appear as if some faces are being stretched off towards an infinitely far away point, hence the term triangling-to-infinity. This can sometime be solved by applying texture mapping because for some reason this can increase the maximum faces in a mesh before this occurs. The certain solution though is to split the mesh into smaller chunks.

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Venetian Blind effect- XWA can have trouble calculating which face is in front of which if there are two or more faces which are roughly parallel and which are not separated by a large enough degree, an example of which would be if you something like a Star Destroyer where you can have a relatively thin box-detail on a flat hull. When XWA has the problems it can end up changing its mind about which face should be shown over the top of the other quite rapidly which produces an effect as if the faces are being interwoven into alternating strips, which as this produces an effect that looks similar to the appearance of a venetian blind is how I refer to the problem.

Vertex Normals- These are the average of the face normals of all faces which use this same vertex and are used by XWA to calculate the lighting and shading of those faces.

Weld - A group of vertices in many 3D modelling packages can be selected and then a Weld tool used which will compare the vertex positions and if two or more vertices are within a set distance of each other combine these vertices into a single vertex. This is very useful in optimising the model to use the least amount of vertices and is something that OPTech automatically does.

XMOD Files- These are the files that XIS uses to install various modifications to a copy of XWA. These are zip files containing the files for the modifications plus a readme, a banner image, and a configuration file to tell XIS what should go where.

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