I am going to do some more work on this following what I've done already.
Then, I thought rather than clog up the Water Planes thread with this, which is related but still a different subject, I would give this its own thread.

Just to reiterate I have successfully changed a smaller world into a larger world by importing these files from a similar larger world.

S3_2AD195F2_00000000_0000000000000001%%+UNKN.bnry
S3_3D8632D0_00000000_0000000000000001%%+UNKN.bnry
S3_05CD4BB3_00000000_0000000000000001%%+UNKN.bnry
S3_06DC847E_00000000_0000000000000001%%+UNKN.bnry
S3_044735DD_00000000_0000000000000001%%+UNKN.bnry
S3_9063660D_00000000_0000000000000001%%+WTXT.wrldtxtrmap

Both started as absolutely empty, unedited flat lush worlds, however, in the smaller one I added four pyramids to the corners of the land to easily identify the size. After the mentioned importation I then added land to the "new" world using the terrain sculpt tool just to confirm that there was extra utile size.

Here is an image of the result...


ps - funny my spell checker doesn't like "utile"

good news bad news...

good news: I have most of the details of these files worked out to the point where I could generate new, larger files although I don't know all the details regarding their use.
bad news: due to the structure of S3_3D8632D0_00000000_0000000000000001%%+UNKN.bnry its clear the max size of a world will be 4096x4096 without a rewrite of the program itself.

nb - while it may be possible to create this basic structure, the file may be uneditable in CAW if it has limitations similar to the initial heightmap usage when starting a new world.

If anyone else wants to give this a try I could write up some info, otherwise I'll just test it first because its a bit of a mish-mash of info.

I could give it a try, but you'll have to write really long info XD but anyway =)

Just to make sure it could be replicated I did it again...
convert a medium size world into a large by importing those 6 files from a larger map...

You can hardly see them but those radio towers define the old limits, plus one extra one get put on by an accidental mouse click,

Green lines are the bounding boxes of the world tiles 4x4 for medium 8x8 for large.
Couldn't zoom out all the way as the liens faded too much, but you can see the idea.

Could you reupload the picture to Photobucket, TinyPic, or some other web site? You can also add it as an attachment. I'm asking since as of this writing, the picture won't show up. I tried to follow the link, and the picture didn't load that way either.

EDIT: It shows up now. Not sure why it didn't before.

More on topic, this is an interesting concept. I wonder what impact it may have on memory and CPU usage. TS3 is only 32-bit so it can only use 4GB.

Ben
Dont have it on the computer I'm on right now but if you still can't see it and can't link to it here... http://picturepush.com/public/6404647 I could do it as an attachment later when I get back on that comp.
IT will be 'interesting' to see what happens re memory issues.
As stated above it will only be possible to go to one more size up anyway due to the way one of the files stores data.

Happy
I will create some files in due course and you can test them out.

One experiment people might like to try is this...
1. create a medium world in CAW, options are your choice but remember/record them.
2. place large objects such as towers [as used above] or pyramids [used in previous exp] right on the four corners of accessible land.
3. create a large world in CAW using the same options as for the other one except of course the size.
4. extract the 6 files named in above post from the large world and save them somewhere easy to find.
5. import those 6 files into the medium world and save.
6. open the medium world in CAW and go to the left or bottom border [should be same orientation but check if not] and lo behold, you can now go further.

Scripts complete but its too late now, big test tomorrow!
Then the answer will be known.

Files generated successfully although poor old js couldn't handle the big 2AD195F2
Imported into Large World to create XL world
Proof is in the image...
see the highlighted tower has an XPos of just over 2047 and land clearly goes beyond, as do the green bounding boxes.

Herein lies the problems...
This system isn't fast enough to handle these large files [new gcard needed] so work is a little clumbsy.
Worse of all it appears that you can't successfully place objects outside of the 2048 size limit [a CAW issue].
Also when you go to save... while it does save the world which can be successfully reloaded it refuses to save the layer file as seen in the 2nd image.

Conclusion it may not be possible due to CAW limitations.
Perhaps a long term project to look into this but, don't hold your breath!

Just out of curiosity, was any more work done with this idea? I started building a medium world and then, a little too late, remembered that the camera-non-routing really only works on large worlds. So I thought I might look into transferring what I had into a larger world but I didn't really think it was possible.

Just follow the directions in the first post, that will make your medium world larger. You can't centralise or control where your existing terrain is though, so results may not be satisfactory.

Hrm, well I'll give it a go and hope for the best! Thanks for the quick reply!

Edit: If I had any terrain editing from my medium world that I wanted to keep (say, some hills), is there a specific file from the 6 listed to leave out? I tried it and it worked just fine, except for everything being flat. Or is this method for flat worlds only? I thought maybe SandrineD was just using total flat worlds for testing but that this potentially could work for non-flat worlds. Thank you!

Nevermind, I exported my heightmap, resized it, and applied it to a new world to use for this. Worked perfectly! Thank you!

Not quite the result you wanted as you'll have to place all of the lots/objects again, but I'm glad you managed to find a solution!

Sorry to dig up this thread, but I made the mistake of using a medium lot since I was having problems with the large one, and now I realized its not enough... i've tried to follow these instructions, but I dont know how to "extract" and "import" files onto the world... if anyone could tell me how to do that in a "description for dummies" kind of way, i'd be very grateful ^^ i've never messed around with anything remotely close to this so i'm kinda slow :s

Use s3pe.

I do use s3pe, I just dont see an option to do that even when I right click around.

Wikerd, on the 'Resource' menu, import> From file or export> To file.

I know how to use the import and export features but I'm having trouble finding those 6 files in s3pe. I've opened the .world file but I have no idea which files they are! They all start with 0x, unlike the mentioned files.
This is probably a dumb question but I'm new to s3pe, can someone help me out/tell me the obvious answer while facepalming? :L

TheScribbler, click on 'Type' in S3PE so that the files are arranged in numerical order. Then you should be able to find files with the type numbers in Sandrine's post, for example 2AD195F2. The 0x just denotes a hexadecimal number.

Thanks a lot simsample! The screenie was especially helpful
Ok I managed to execute it successfully but the result was somewhat puzzling, I need some help with this and thank you very much to anyone who gives any advice!
Basically I'm trying to extend the map size of this island (attached picture) to where the beige line is so I can expand the island. The current map size limits are roughly halfway between the red cross and the green line. (ignore the other markings)
My first attempt was with a medium-size desert-filled world with the specified files and it kind of worked but resulted in only the path terrain paints being transferred onto the flat desert.:/
Does anyone know how this can actually be done? Or is this method for non-island worlds only?
The world is made CAW-editable by using simsample's second "editing premade worlds" method.

Btw the world isn't mine but the creator is abandoning it and releasing the CAW files sometime soon.

The problem with this method is that you cannot choose the direction in which the world is extended, so you may find it easier to start over and use your existing heightmap (but enlarge it, so that it will fit a larger sized world. If you use a photo editor you can control where the original part of the island is, using that method).

For the terrrain paints, again you need to export your terrain map from your existing world and edit it to fit the new world. It may be easier to start from scratch! This method is not easy and has a lot of limitations, but is the only way of making an existing world larger.

If the terrain paint maps can be imported as layers with the height map in a graphics editor, the layers can be grouped and edited simultaneously, and then each layer could be saved on its own when finished. It would look different in the larger scale, but still be a good starting place.