1) Characters
I'll explain this with an example. I have a character which replace the images and all three dat.-files of John and I want to change this character into an Add-on.

First thing you have to do is changing the id-numbers. To do this, go to the data-folder and open data.txt. Copy these lines (they're spread out over the whole file):

     id:   2   type: 0   file: data\john.dat
     id: 200   type: 3   file: data\john_ball.dat
     id: 214   type: 3   file: data\john_biscuit.dat

Now paste them somewhere in the object-part and rename them like this:

     id: 400   type: 0   file: data\newchar.dat
     id: 401   type: 3   file: data\newchar_ball.dat
     id: 402   type: 3   file: data\newchar_biscuit.dat

The oid part of an opoint references the id-number of the object that is created. Because you changed the id-numbers of the attacks in data.txt, you also must change the oids in the dat.-files. Open newchar.dat with the Data Changer and search for "oid:" (without quotes) with the search function (Crtl + F / F3). If you see the number 200 after an oid, replace it with 401 and if you see 214, replace it with 402. All other oid's can stay the same.

There are some cases where you may have changed the oid and the id of an object, but the original object is created instead. This occurs when the object is activated in a ratio by a special hit_Fa: function (Overwhelming Disaster...) and can't be changed easily. You'll need more DC knowledge to solve this in an acceptable way.

Finally, rename the pictures to "newchar_xyz.bmp". Then open the dat.-files. At the top of the file you'll see the image-list, change the title of the images.

This should do it in most cases. If you just have some images to replace, copy the data of the existing character and continue as I described above. If you just have new dat.-files you don't have to care about the image stuff...


2) Backgrounds
If you have some pictures which should replace an existing background you can also change this to an add-on background. I take Lion Forest as example since it's often replaced with a darker version.

Begin by copying the entire "lf"-folder (Lion Forest) and rename it to "nf" (Night Forest). Then put the replacement pictures into this folder. Next open the bg.dat with the Data Changer and change the locations of the pictures from "bg\sys\lf" to "bg\sys\nf". Don't forget the shadow picture in the head. You can also change the name to "Night_Forest" if you want.

Finally, open data.txt and scroll down to the background-part. Add a line for the new background like this:

     id: (not important here)   file: bg\sys\nf\bg.dat

3) Weapons
Well, dealing with weapons is always a problem because of one thing: broken_weapon.dat. Broken weapon data depends a lot on the source code. So if you replace a weapon into an add-on (you should know how to do this now) you won't have any broken_weapon sprites. It's your choice...