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Junction25 version 1.6.

Release date: 23rd March 1998.

Notes on terms used in Junction25.

Whenever you alter any area of a map, the dialog box will always have a section allowing you to specify the height of the cube you want to modify. Junction25 considers the cube on the lowest level to be at height 0. Each column consists of six cubes, thus the highest cube is at height 5. This is shown in "diagram 1".


If you've seen alternative explainations of this, you would probably be better off sticking to Junction25's system, since this seems to be the most logical one to use. If any of you have used M1, you will see that it also uses the same system as Junction25.

If you've tried hacking away at the 'mission.ini' file, you will notice that it uses 'inverted' heights. For example, a height coordinate of 0 is the heighest height the player can start at. This would correspond to height 5 in Junction25.

When dealing with slopes, you will see that the top and bottom heights are specified in decimal fractions. This is because slopes can start at intermediate heights within a cube. In this case, Junction25 takes the bottom the cube at height 0 to be height 0.000, and the top the cube to be at height 0.999. Thus, the height of the bottom of the cube at height 1 will correspond to 1.000, and so on, upwards. This is shown in "diagram 2" and "diagram 3".


Roads.

To create a road, you will normally change the top texture of a cube to look like a road.

Next you should change the attribute of the cube ABOVE the cube with the road texture on it. This is an important point to remember. Many of the attributes work the same way. For a road, you would change the cube attribute to vehicle. This is shown in "diagram 2".

Cars are affected by the "vehicle direction" attribute of the cubes they move into. For example, if a car moves into a cube with "vehicle direction" set to "north", the vehicle will with carry on north, or turn north. If multiple directions are specified, the vehicle choose a random direction from the ones specified.

Pavements, "player only", water, solid and "no floor" all work in the same way.

Slopes.

Making slopes is relatively easy. However, it may take a little practice before you get used to using them.

Firstly, you must work out the starting height - the bottom height - of the slope. This would be 0.000 in "diagram 3", for example.

Secondly, work out the height of the top of the slope. This would be 1.000 in "diagram 3", for example.

Finally, select the gradient of the slope. Anything can move onto a slope with the smallest gradient. Only people and bikes can move onto slopes with the next heighest gradient. Finally, the steepest gradient is used for things like roofs.

You may also want to change the brightness of a slope to get that "3d" effect, and also keep tabs on the locations of slopes while using Junction25.

It should also be noted that when changing the attributes of the sloping cubes, you should NOT change the attribute of the cube ABOVE the slope, but you should change the attribute of the cube that is sloping. This differs from the normal way attributes work.

To make a slope you can jump off, change the attributes of the cube just below the end of the slope. Do NOT select the cube that is sloping on the edge of the slope, but select the cube NEXT TO THE END of the slope.

You can always refer to the original maps if you get stuck.

The "mission.ini" file

Note that you should use the blank mission.ini provided with Junction25 in order to play your new maps.

- Player start position

This can be changed in the mission.ini file. Simply locate the line containing the word "PLAYER" and change the coordinates in the brackets.

An important point here, is that the height coordinate (the third one along), is the inverse of Junction25's height coordinate. For example, if you have a cube at height 0 with a pavement texture on its top, you will want to place the player at height 1. You then perform the following calculation to work out the height coordinate to use in the "PLAYER" line:

"PLAYER" line height = 6 - Junction25 height

So, to place the player at Junction25 height 1, change the "PLAYER" line height coordinate to 5. For "New York city", the height of most roads are 2, so the player you start at height 3. After doing the above calculation, this works out as height 3 to put in the "PLAYER" line.

Playing your new maps

You should save your new map to the GTA\GTADATA directory, where you installed Grand Theft Auto. Save the map as:

"nyc.cmp" for New York city,

"sanb.cmp" for San Andreas,

"miami.cmp" for Vice City

Next, go into the game and choose one the three locations, and go ahead and play your map!

If you want to save your map with a different name, you may always change the name of the map in the "mission.ini" file. For example, the start of the "mission.ini" file specifies "nyc.cmp". You can change this to be the name of your map. You MUST save your map to the GTADATA directory in any case.

Traffic lights and junctions

Basically, these consist of a box surrounding the junction with the "traffic light" attribute switch on. You must then place a traffic light static object onto one corner of this box. You should also use the vehicle attribute for the junction box as well.

For an example of how this is done, look at any traffic light junction in an original map.

Hospitals, police stations, fire stations and cops

Specify the "hospital" attribute ABOVE a cube that is a pavement. You should also do the same for police stations.

Fire station cubes should be specified one cube ABOVE the cube where fire engines will appear on the map. So the get a fire engine to appear at height 2, specify the "fire station" attribute at height 3.

Unfortunately, cops will NOT appear on your new maps. This is more complicated than it first seems, since the cop's Artificial Intelligence comes into play. We will probably include support for cops in the next version of Junction25. Sorry! It is possible, however, to get cops to generate, with some tweaking of the map file with a hex editor. Try taking a look at DMA's Cityscape documentation for details.

Map compression

It is possible to make so many changes to a map that the map can no longer be saved out uncompressed. Therefore, the map must be compressed before saving out. On a Pentium 133 with 32 Megs of RAM, compressing an original GTA map takes around one to two minutes.

Small changes can usually be saved out without the need for compression. However, there will come a time when the map must be compressed, so beware!

Fences and Signposts

Signposts can be made using the 'Transparent/Flat' checkbox on the attributes dialog. As well as making the black on textures transparent this effectively flattens the cube so that only the North, West and Top sides have textures on. The textures set for the South and West faces will appear as the inside of the North and East sides allowing you to have a two sided sign with different textures on each side. To make a fence just choose fence textures for the North and South, or East and West sides, set the 'Transparent/Flat' checkbox and make the cube solid. When using fence textures the solid type just makes the fence edge impassible, not the whole cube.