Are there any guidelines on the object editor?
A guide? No, not for AHIII and I don't remember one for AHII.
That's for the bad news. For the good news...
Can terrain tiles be modified?
Yes. Okay to create new terrain tiles, objects, fields, ect. for any arena except the MA. If you have a specific MA idea, you should contact HT.
In no particular order ...
Most of what I learned about the OE was from using it. It isn't that hard, though the switching between placing live buildings on an object tile and adding/placing trees on the same tile is not intuitive and always takes me several attempts to make the switch.
In the early "Open Beta Test" forum you'll find discussions about how texture work. You can't do much without that info. For skinning buildings etc. See the Custom Skins forum. What applies to skins also applies to building though you can see some results with only the diffuse bitmap.
Custom Field and Strat objects are beyond the scope of this discussion as they start with 64 sub-objects per square mile to accommodate collisions. But keep in mind how your summer airfield will look surrounded by your custom terrain tiles.
Terrsets - start in the TE and export the terrset used in your currently loaded terrain.
Find the files in the "exports" folder iirc and inspect the results.
You'll find text files, bitmaps and subfolders.
My biggest (read as most frustrating) stumbling block was creating all the various bitmaps needed for the ground. There are grayscale bitmaps for things like gravel and cobblestone ground, and bitmaps for clumps of grass and tomatoes. These are called out in the appropriate exported text files, force them open in NotePad to view. The same applies to opening the speedtree files if you want to look at them too.
The OE can open the individual tiles (sand etc) as a package along with their associated parts.
Everything starts by creating a new tile even if you only want to convert a single new ac3d custom object to the game: The OE asks you to set the tiles properties, is it a terrain tile or an object, size and terrset etc. Save the empty tile before you begin, the OE will suggest a location folder.
For creating and adding a static plane, building etc., the OE can import an ac3d file (extension .ac).
To my knowledge, no one has attempted creating speedtree trees or objects.
Note that almost every AH building has an equivalent speedtree building for placement in a terrain tile.
For any tile, whether a new field layout, strat object or terrain tile, you must create 5 textures for each tile. That's 20 sets for a terrset. The last time I asked HT, he said I could not increase the size of the 508x508 bitmaps as the game combined all 16 into a single 2048x2048 bitmap. Roads and paths are impossible on a 508 tile at proper scale.
Textures Needed:
mytile.bmp_______Diffuse ___ _Basic image
mytile_D.bmp_____ _D aka _a0 _Detail Map asphalt roads etc
mytile_S.bmp_____ _S aka _b1 _Sun - Specular Map, flat to shiny terrain features
mytile_n.bmp____ _n_________ _Normal map, bump map and 3d effects
mytileclutter.bmp__Clutter___ _Farm crops, weeds, cracked mud etc
_a0 and clutter maps are grayscale using values 0, 16, 32, 48, ...240.
b1 is sun reflections Specular , is the only map that uses the full range of
grayscale. 129 is neutral, lower is darker, higher is brighter.
Note: using the a0,a1,b0,b1 nomenclature forces the bitmap into the
specified slot while using the intuitive D and S nomenclature might not.
terrdet (used for terrsets)
0 00 sandsnow.bmp
2 10 mud.bmp
3 20 cracked.bmp
4 30 dirtroad.bmp
5 40 grassrock1.bmp
6 50 grassrock2.bmp
7 60 grass1.bmp
8 70 grass2.bmp
9 80 moss.bmp
10 90 leaves.bmp
11 A0 ivy.bmp
12 B0 gravel.bmp
13 C0 rock1.bmp
14 E0 farm1.bmp
15 F0 farm2.bmp
16 FF noise.bmp
objdet (used for object tiles)
0 00 asphalt01.bmp
2 10 asphalt03.bmp
3 20 concrete01.bmp
4 30 concrete02.bmp
5 40 3secconcrete.bmp
6 50 4secconcrete.bmp
7 60 grass1obj.bmp
8 70 dirt02.bmp
9 80 gravel01.bmp
10 90 rocks.bmp
11 A0 grassrock2.bmp
12 B0 brick05.bmp
13 C0 brick02.bmp
14 D0 dirtroad.bmp
15 E0 concrete04.bmp
16 F0 dirtroad.bmp
