1. You want to be careful not to modify the existing scn files so it doesn't affect your ability
to play the original scenarios from the game.
2. You want to make sure your opponent is aware of the changes you make and agrees to them before starting the game.
The easiest way to modify a scenario file is to open it with the Scenario Editor. We'll go through a step by step procedure on doing this. When you start the Editor you get a window that looks like the figure below. I'm going to select 002 1BR_Bull Run(Historical).scn and open that file.
Once you open the file the first thing you want to do is to save it under a new name. Using the Save As function in the File menu give it a name that indicates what scenario it was developed from, later I'll show you how to make notes in the Editor to indicate what was changed. For now I'll save it as 002a 1BR_Bull Run(Historical).scn as shown in figure 2 below.
Now you can make the changes you want to make to the scenario without affecting the original scenario file.
I am not going to go over using the Editor in much detail, I think the Help files do a good job of explaining things for the most part. I do want to point out one thing that I think is important when modifying a scenario. If you go to the Scenario tab at the top and click on Description you'll see a window like that in figure 3 below.
This is the information that appears when you are browsing the scenario list to start a new game.
So when you are just modifying a scenario this is where you want to make your notes on what you did to the original
scenario so people know what changes you made.
In the Author section I normally leave the original name and add "modified by Ken Miller." This way I am still giving credit to the original author while noting that I have changed it.
Then in the Description itself I add additional text explaining what changes were made and why. Let's say I wanted to release some of the fixed units earlier. In that case I would add at the end of the original description "Hunter's Division released earlier to reflect better handling of the predawn march by the union forces." So you might want to do something similar when you modify existing scenarios.
Next I'd like to run you through the process of developing a new scenario from scratch.
The first thing you want to do is determine which map, oob and pdt file you want to use for your scenario.
Remember you can load a modified pdt file into the game engine so if your scenario will occur on different dates
than the original pdt file and you want to use the weather function you can copy the old pdt, rename it, modify it
using the information provided elsewhere on this site as a guide then use your new pdt in your new scenario.
With the release of the JTS Overland game the map and oob files appear to have been opened up again. Currently those games that have been updated to version 2.0 allow map and oob files other than the originals to be loaded, provided the map file has the correct checksum modifier applied. For more information on this see the sections on maps.
When you first open the editor you'll see something like the image below.
If you close the Open window by clicking on the X in the upper right corner, then go to File then New you'll see the window below listing the available map files.
This window allows you to choose the map file for your scenario. I have selected Antietam.map. Once you select the map the new window that opens
allows you to choose the oob file you want to use. Once you've selected that the last choice to be made is which pdt file you want to use as shown in the figure below
Once you have selected your map, oob and pdt file the next thing you'll see is the map in the background and the Header window shown below.
The Header window is where you set the date and time of the first turn of your scenario, how many
turns it will last, the VP for casualties as well as the victory conditions and the starting ammo for both sides.
A couple things to keep in mind about gun ammo levels when designing your scenario.
1. Base your ammo per UNIT. If the Artillery Ammo by Cannon option is chosen the game engine automatically adjusts your ammo level for the number of guns in each unit.
2. Most of the older games I played that had good ammunition rules figured a battery could fire for @ 2 hours with it's limber supply. (Most of the accounts I've read on the Gettysburg 3rd day indicate this was about how long the bombardment lasted so that seems to be a good estimate.)
3. These games normally also allowed for a resupply feature from Army reserve wagons, CSA figures normally were about 1.25-1.35 additional supplies while USA were somewhere between 1.5-1.75.
4. Batteries that start on the map have only the ammo in the supply. Reinforcements add additional ammo to the supply, it used to be 4 ammo per gun unit but I recently checked this using Gettysburg 2.0 and Corinth 2.0 and it now appears to be 6 ammo per unit with that new version.
So as a good basis for gun ammo you should
1. Keep track of the artillery units starting on the map and figure 10 ammo for each of these.
2. Keep track of reinforcing artillery units, remember they will add 4 (before 2.0) or 6 (after 2.0) ammo when they arrive on the map, so add 4 to your supply for each reinforcement artillery unit.
3. For multiple day battles you have to decide how much of a reserve to have, using the total number of artillery units, multiply by 10 to determine their ammo then multiply that by 1.3 to get the CSA reserve and 1.7 to get the USA reserve, add that to the original supply and you should be pretty good.
Keep in mind these were for 2-3 day battles, if you plan something longer you may want to increase the reserve.
4. For smaller actions you can reduce the reserve as these were normally carried at the corps/army level so for a corps or lower command level action just double your initial supply rather than using the multiplier above. For single day battles a much smaller reserve would be suggested.
For help in figuring small arms ammo for a scenario I suggest Robert Frost's Ammunition Algorithym available here
You don't have to fill in all this information right away, you can always return to the Header window from the Scenario menu on the top of the editor menu bar. Once you close the Header window you will see the Scenario Description window shown earlier in figure 1. It too is available under the Scenario Menu. Once you've closed the Description window you will see the window below.
This shows the Unit Dialog window that allows you to place units on the map. Like the Header and Description window this one can be closed and reopened, only it is located on the Command menu.
The next you would want to do is save your scenario using the Save As function in the File Menu. You are now ready to begin development of your own scenario. If you use the Help files you should be able to figure out how to do most functions involved in building your own scenario.
The last thing I want to cover is the easy way to change the PDT file for a scenario. This is the one part of a scn file that you can change directly using a text editor without causing problems with the file. To do this you open the scn file with a text editor, once again the first thing you want to do is rename the file in the same manner as was described previously. To do this you use the Save As function under the File menu. After that you should have something like this displayed in your text editor.
Battle of 1st Bull Run (Manassas), July 21st, 1861
1861 7 21 3 0 0 0 1 38
10 20 30 2
10 20 30 2
-1000 -500 500 1000
4 4 0 0 4292 0 0
1st Bull Run.oob
0 0 0 0 0 0 0 0 0 0
2 2 2 2
If you change the name of the pdt file in the eleventh line you can then save the file, when opened it will use the new pdt file you specified. Next you'll want to open it with the Scenario Editor and make a note in the Description explaining that the new scenario uses a modified pdt file and maybe noting what was modified in the pdt file.
This covers the basics on starting the Scenario Editor, opening a scenario file and modifying it's Description, starting a completely new scenario and changing the pdt file used by a scenario. The only other advice I can give you is to try modifying or creating a scenario. I've found the best way to learn to use the Scenario Editor is to do just that, use it. You'll quickly find out what works and what doesn't and the Help Files and manual can assist you. Just remember when you open a scenario file to save it under another name before you start making changes to keep from corrupting your original game files. Finally once you've designed your scenario it's a good idea to playtest it several times to see if it needs tweaked for play balance purposes, especially if you plan to post it somewhere for others to download.