New 3D file conversion Project

[Xela]

Here is is short introduction to another interesting project I have to deal with. In order to gather some interest and possibly your kind and greatly appreciated assistance I'll try to briefly describe what is all about.

I am a member of TSH modding group doing some work on pretty good and rather well known military flight simulation of F/A-19 Hornet by Janes and published back in 1999 by EA. The sim has a priopriatory format of file called 3DG. Some time ago someone made converter to 3DS and viewer called ZEdit. It is available and has entire source code consisting of many files. The program converts 3DS to 3DG and viceversa and also is capable of additional import of X and SRF format files and conversion to 3DG.

The problem is that ZEdit it is not fully capable of importing animation and LODs (level of detail models) . This is not supported and not implemented. We are looking for any advice and support in our mission to correct it and our goal is to have it.

At the moment I would like myself and whoever else interested here just to get acquainted with precise structure of 3DS and 3DG formats just by looking and analysing those pieces of code on this forum.
So, shall we try

[Homer]

Just surfing through... here you go.....

http://www.geocities.com/aliens_can_dunk/3dlinks.html

[Xela]

Thank you for interesting and what I call "kitchen" link. I stumbled accross that once before the resources pertaining to 3DS documentation very good indeed.

Just without going into the details, but how do you think such a converter is being made? Do you think that general terms there must be a fields of data comparison between two formats? Then similar fields are identyfied "highlighted" and linked. Information from one format is then "fed" into the fields of another format. The sequence and order of such similar fields do not matter, but the the content does.

Is this more or less your understanding how such a converters are written up?

[OneOneSeven]

Essentially what a converter will do is read the raw geometry and UVW coordinates (remember, it's in binary >.<) from your file to be converted, and will try and re-arrange them as best it can in order to create a file that conforms to the specifications of the new format. You'd also need to know a bit about how the game works before importing anims, as they may use bones. LOD should be pretty easy, I'd be willing to bet you could find locations to begin reads in the header somewhere... If you know how it designates where to begin reading the main model data, you could probably compare that to the rest of the header and look for similarities in other chunks.

[Xela]

It is indeed happy coincidence that after so much time ( my post was made in April), just day before yesterday I decided to go back to revisit this project.

And in fact after few hours of gawking into the hex code of an example file I managed to decipher some details. I have recognised in the detail how geometry is recorded and written - first as a list of binary coordinates for all vertices , and then it has been "fleshed" out and grouped into the polygons outlining true shape of the model.

That list contains: the main most detailed 3D object and then lower iterations of the same as LOD 2 and 3 ever simple and simple.
The list is even using the same vertexes of the complex shape, but the polygons are new.

However, as you write :

LOD should be pretty easy, I'd be willing to bet you could find locations to begin reads in the header somewhere... If you know how it designates where to begin reading the main model data, you could probably compare that to the rest of the header and look for similarities in other chunks.

I FAIL to see how the game engine and possible the exporter may differentiate and recognise when to use or separate them cleanly?

I am willing to copy here all what was deciphered so far as the best would be to look at the real example. Stand by ....

[Xela]

Which, without further ado.... I do
Below is the file in its "native" form except that I formated it a little for better understanding whats there.

BUNKERB.3dg FROM F18

6f 2a 79 41
00 00 00 00
00 00 00 00 00 00 00 00 00 80 03 00 02 00 00 00

52 55 53 54 30 31 2e 50 43 58 00 00
00 00 00 00
00 00 00 00
00 00 00 00
00 00 80 3f
00 00 80 3f

43 4f 4e 30 33 2e 50 43 58 00 00 00
00 00 00 00
00 00 00 00
00 00 b5 b4
00 00 80 3f
00 00 80 3f

00 00 00 00
0c 00 00 00

db 49 b2 40
3d 25 27 40
16 93 48 c1
db 49 b2 40
3d 25 27 40
00 00 00 00
db 49 b2 c0
3d 25 27 40
00 00 00 00
db 49 b2 c0
3d 25 27 40
16 93 48 c1
52 dc de c0
00 00 00 00
52 dc 5e c1
52 dc de c0
00 00 00 00
00 00 00 00
52 dc de 40
00 00 00 00
52 dc 5e c1
52 dc de 40
00 00 00 00
00 00 00 00
db 49 b2 40
3d 25 27 40
16 93 48 41
db 49 b2 c0
3d 25 27 40
16 93 48 41
52 dc de c0
00 00 00 00
52 dc 5e 41
52 dc de 40
00 00 00 00
52 dc 5e 41
00 00 00 00
00 00 00 00
00 00 00 00

06 00 00 00 00 00 00 00 00 00 80 3f

00 00 00 00
3d 25 27 40
e1 e1 61 bf
f3 f0 f0 3e
00 00 00 00
48 a4 c4 40
00 00 00 00
f7 f0 f0 3e
e0 e1 61 bf
47 a4 44 41
e1 e1 61 3f
f3 f0 f0 3e
00 00 00 00
48 a4 c4 40
00 00 00 00
f7 f0 f0 3e
e0 e1 61 3f
47 a4 44 41

00 00 00 00 00 00 80 3f

00 00 00 00 00 00 00 00
09 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
04 00 01 00 00 00 00 00
06 00 02 00 00 00 00 00
07 00 03 00 00 00 00 00
01 00 00 00 00 00 00 00
05 00 01 00 00 00 00 00
0b 00 03 00 00 00 00 00
0a 00 04 00 00 00 00 00
06 00 00 00 00 00 05 00
0c 00 00 00 00 00 00 00

33 a3 d9 44
00 00 05 00
89 00 01 00
33 a3 d9 44
66 3a a3 45
00 00 05 00
d6 00 02 00
66 3a a3 45
53 0b 26 4d
00 00 00 00

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 04
00 00 00 00 00 00 00 00 80 3f
01 00 00 00 00 00 00 00 00 00
02 00 00 00 80 3f 00 00 00 00
03 00 00 00 80 3f 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 01 00 00 00 00 04
04 00 00 00 00 00 00 00 80 3f
03 00 00 00 00 00 00 00 00 00
02 00 00 00 80 3f 00 00 00 00
05 00 00 00 80 3f 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 00 02 00 00 00 00 04
06 00 00 00 80 a4 00 00 80 3f
00 00 cd cc cc 3d 40 8e 63 3d
03 00 66 66 66 3f 40 8e 63 3d
04 00 00 00 80 3f 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03 00 03 00 00 00 00 04
07 00 00 00 80 3f 00 00 80 3f
01 00 00 00 80 3f 00 00 00 00
00 00 00 00 00 00 00 00 00 00
06 00 00 00 00 00 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 00 00 00 01 04
01 00 00 00 80 3f 00 00 80 3f
08 00 00 00 80 3f 00 00 00 00
09 00 00 00 00 00 00 00 00 00
02 00 00 00 00 00 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 05 00 00 00 00 04
05 00 00 00 80 3f 00 00 80 3f
02 00 00 00 80 3f 00 00 00 00
09 00 00 00 00 00 00 00 00 00
0a 00 00 00 00 00 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03 00 06 00 00 00 00 04
0b 00 00 00 00 00 00 00 80 3f
08 00 00 00 00 00 00 00 00 00
01 00 00 00 80 3f 00 00 00 00
07 00 00 00 80 3f 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 00 07 00 00 00 00 04
0a 00 00 00 80 3f 00 00 80 3f
09 00 66 66 66 3f 40 8e 63 3d
08 00 cd cc cc 3d 40 8e 63 3d
0b 00 00 00 80 a4 00 00 80 3f

00 00 00 00

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 04
00 00 00 00 00 00 00 00 80 3f
08 00 00 00 00 00 00 00 00 00
09 00 00 00 80 3f 00 00 00 00
03 00 00 00 80 3f 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 01 00 00 00 00 04
04 00 00 00 00 00 00 00 80 3f
03 00 00 00 00 00 00 00 00 00
09 00 00 00 80 3f 00 00 00 00
0a 00 00 00 80 3f 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 00 02 00 00 00 00 04
06 00 00 00 80 a4 00 00 80 3f
00 00 cd cc cc 3d 40 8e 63 3d
03 00 66 66 66 3f 40 8e 63 3d
04 00 00 00 80 3f 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03 00 06 00 00 00 00 04
0b 00 00 00 80 3f 00 00 80 3f
08 00 00 00 80 3f 00 00 00 00
00 00 00 00 00 00 00 00 00 00
06 00 00 00 00 00 00 00 80 3f

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 00 07 00 00 00 00 04
0a 00 00 00 80 3f 00 00 80 3f
09 00 66 66 66 3f 40 8e 63 3d
08 00 cd cc cc 3d 40 8e 63 3d
0b 00 00 00 80 a4 00 00 80 3f
00 00 00 00

00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 05 00 08 00 00 00 01 04
06 00 00 00 00 00 00 00 80 3f
0b 00 00 00 00 00 00 00 00 00
0a 00 00 00 80 3f 00 00 00 00
04 00 00 00 80 3f 00 00 80 3f

00 00 00 00 00 00 00 00

And now the same but with my commentary what
I know ,
I think I know and
I'm dumb about :

BUNKERB.3dg FROM F18



6f 2a 79 41 //here is ID
00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 02 00 00 00 //surely many things here, but it ends on that there are 2 materials which in this case are textures

52 55 53 54 30 31 2e 50 43 58 00 00 //name of the 1st material, which here is texture RUST01.PCX,
00 00 00 00 00 00 00 00 //I think also that 8x00 which follow are part of this string 20 char long ...saw somewhere

00 00 80 3f //now this is little mystery but I think this is float = 1.00 and it indicates that full size of texture is used lengthwise and then hightwise
00 00 80 3f

43 4f 4e 30 33 2e 50 43 58 00 00 00 //same as above for the 2nd material / texture, 20 char for name
00 00 00 00 00 00 00 00
00 00 b5 b4 //new element here, not sure
00 00 80 3f
00 00 80 3f //same as above for the 2nd texture

00 00 00 00 //???????

0c 00 00 00 //here is total number of vertices 12 for the model in its higher LOD (level of detail, pls ref. sketch)
// here go floats with XYZ coordinate for each of 12 vertices, I have manually verified that on the model and I will translate to DEC and label them on sketch

db 49 b2 40 //vertex 00
3d 25 27 40
16 93 48 c1
db 49 b2 40 //vertex 01
3d 25 27 40
00 00 00 00
db 49 b2 c0 //vertex 02
3d 25 27 40
00 00 00 00
db 49 b2 c0 //vertex 03
3d 25 27 40
16 93 48 c1
52 dc de c0 //vertex 04
00 00 00 00
52 dc 5e c1
52 dc de c0 //vertex 05
00 00 00 00
00 00 00 00
52 dc de 40 //vertex 06
00 00 00 00
52 dc 5e c1
52 dc de 40 //vertex 07
00 00 00 00
00 00 00 00
db 49 b2 40 //vertex 08
3d 25 27 40
16 93 48 41
db 49 b2 c0 //vertex 09
3d 25 27 40
16 93 48 41
52 dc de c0 //vertex 0A
00 00 00 00
52 dc 5e 41
52 dc de 40 //vertex 0B
00 00 00 00
52 dc 5e 41

// here goes long block I do not understand - need help !!!
00 00 00 00
00 00 00 00
00 00 00 00

06 00 00 00 00 00 00 00 00 00 80 3f

00 00 00 00
3d 25 27 40
e1 e1 61 bf
f3 f0 f0 3e
00 00 00 00
48 a4 c4 40
00 00 00 00
f7 f0 f0 3e
e0 e1 61 bf
47 a4 44 41
e1 e1 61 3f
f3 f0 f0 3e
00 00 00 00
48 a4 c4 40
00 00 00 00
f7 f0 f0 3e
e0 e1 61 3f
47 a4 44 41

00 00 00 00 00 00 80 3f

00 00 00 00 00 00 00 00
09 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
04 00 01 00 00 00 00 00
06 00 02 00 00 00 00 00
07 00 03 00 00 00 00 00
01 00 00 00 00 00 00 00
05 00 01 00 00 00 00 00
0b 00 03 00 00 00 00 00
0a 00 04 00 00 00 00 00
06 00 00 00 00 00 05 00
0c 00 00 00 00 00 00 00

33 a3 d9 44
00 00 05 00
89 00 01 00
33 a3 d9 44
66 3a a3 45
00 00 05 00
d6 00 02 00
66 3a a3 45
53 0b 26 4d
00 00 00 00


// here goes lis of the surfaces for enitre model and all LODS .Basically it says that vertex 00 01 02 03 make 4 vert surface and material it is 01 wchich is 1st texture RUST01. There are other important flags here but I did not deciphered them yet. Again, 80 3f tells that full extend of texture is used ... I think. I will also label them and show on sketch. NOTE: the same vertices are used in 3 LODS

//Here goes 12 vert and 8 polygons for VERY HIGH DETAIL LOD
//Poly A
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 04
00 00 00 00 00 00 00 00 80 3f
01 00 00 00 00 00 00 00 00 00
02 00 00 00 80 3f 00 00 00 00
03 00 00 00 80 3f 00 00 80 3f
//POLY B
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 01 00 00 00 00 04
04 00 00 00 00 00 00 00 80 3f
03 00 00 00 00 00 00 00 00 00
02 00 00 00 80 3f 00 00 00 00
05 00 00 00 80 3f 00 00 80 3f
//POLY C
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 00 02 00 00 00 00 04
06 00 00 00 80 a4 00 00 80 3f
00 00 cd cc cc 3d 40 8e 63 3d
03 00 66 66 66 3f 40 8e 63 3d
04 00 00 00 80 3f 00 00 80 3f
//POLY D
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03 00 03 00 00 00 00 04
07 00 00 00 80 3f 00 00 80 3f
01 00 00 00 80 3f 00 00 00 00
00 00 00 00 00 00 00 00 00 00
06 00 00 00 00 00 00 00 80 3f
//POLY E
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 00 00 00 01 04
01 00 00 00 80 3f 00 00 80 3f
08 00 00 00 80 3f 00 00 00 00
09 00 00 00 00 00 00 00 00 00
02 00 00 00 00 00 00 00 80 3f
//POLY F
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 05 00 00 00 00 04
05 00 00 00 80 3f 00 00 80 3f
02 00 00 00 80 3f 00 00 00 00
09 00 00 00 00 00 00 00 00 00
0a 00 00 00 00 00 00 00 80 3f
//POLY G
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03 00 06 00 00 00 00 04
0b 00 00 00 00 00 00 00 80 3f
08 00 00 00 00 00 00 00 00 00
01 00 00 00 80 3f 00 00 00 00
07 00 00 00 80 3f 00 00 80 3f
//POLY H
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 00 07 00 00 00 00 04
0a 00 00 00 80 3f 00 00 80 3f
09 00 66 66 66 3f 40 8e 63 3d
08 00 cd cc cc 3d 40 8e 63 3d
0b 00 00 00 80 a4 00 00 80 3f

00 00 00 00

//Here goes 8 vert and 5 polygons for HIGH DETAIL LOD
//POLY I
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 04
00 00 00 00 00 00 00 00 80 3f
08 00 00 00 00 00 00 00 00 00
09 00 00 00 80 3f 00 00 00 00
03 00 00 00 80 3f 00 00 80 3f
//POLY J
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 01 00 00 00 00 04
04 00 00 00 00 00 00 00 80 3f
03 00 00 00 00 00 00 00 00 00
09 00 00 00 80 3f 00 00 00 00
0a 00 00 00 80 3f 00 00 80 3f
//POLY K
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 00 02 00 00 00 00 04
06 00 00 00 80 a4 00 00 80 3f
00 00 cd cc cc 3d 40 8e 63 3d
03 00 66 66 66 3f 40 8e 63 3d
04 00 00 00 80 3f 00 00 80 3f
//POLY L
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03 00 06 00 00 00 00 04
0b 00 00 00 80 3f 00 00 80 3f
08 00 00 00 80 3f 00 00 00 00
00 00 00 00 00 00 00 00 00 00
06 00 00 00 00 00 00 00 80 3f
//POLY M
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 00 07 00 00 00 00 04
0a 00 00 00 80 3f 00 00 80 3f
09 00 66 66 66 3f 40 8e 63 3d
08 00 cd cc cc 3d 40 8e 63 3d
0b 00 00 00 80 a4 00 00 80 3f

00 00 00 00

// and finaly 4 vert and 1 polygon for MEDIUM DETAIL LOD

//POLY N
00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 05 00 08 00 00 00 01 04
06 00 00 00 00 00 00 00 80 3f
0b 00 00 00 00 00 00 00 00 00
0a 00 00 00 80 3f 00 00 00 00
04 00 00 00 80 3f 00 00 80 3f

00 00 00 00 00 00

and sketch to make it clearer (I add labels later).



[/quote]

[OneOneSeven]

However, as you write :

LOD should be pretty easy, I'd be willing to bet you could find locations to begin reads in the header somewhere... If you know how it designates where to begin reading the main model data, you could probably compare that to the rest of the header and look for similarities in other chunks.

I FAIL to see how the game engine and possible the exporter may differentiate and recognise when to use or separate them cleanly?

A loader is a lot less complex than many people think. Essentially it reads the locations of the ends of data streams from the initial file segment. (the header, to use a technical term.) Then, the program simply goes from the beginning of where you tell it to until it reaches the end of the specified stream, which doesn't even have to be the end of the file. In theory, you can encode as much info as you want into the model, you just have to explain to your program how to USE the read data. I realize this isn't the best explanation, but I know it's better than "Trust me." If anyone can come up with a better way to phrase it please do so.

[Xela]

No your explanation is quite fine. I realise that the loader MUST have the info what model to load and when. In situation when LODs are involved that trigger is usally the distance from the observer. And I know from my previous experience that most of the time this is encoded somewhere in the file usually on the begining of the file.

But here I have the entire file, I have 3 LODs, I know where the information about them reside. Yet so far, I failed to see where the distance or that trigger when to display LOD is hiding.

[OneOneSeven]

Aaah-- That's usually within the game executable itself. Only rarely will models swap detail levels at different intervals, it's usually faster to say "If it's this far away use this model." Some simple stuff might have a 'flag' or something that says it doesn't have a LOD (maybe you're dealing with a cube or something) at which it will skip, but this is mostly dependent on the level of performance for the rest of the game.