GRAW: CUSTOM CONTENTS OVERVIEW by: wilhelm wintertidh/GRIN AB 2006

Overview of the overview

Ok, so you want to import your own contents into GR:AW pc? Not a problem! Well, it is a tiny bit of a bother really, but not as bad as you might think when you first look at it!

This tutorial will do its best(funny how a tutorial, all of a sudden can get a life and persona of its own) to get you sorted out.

What you need to get a prop, a house, a weapon or a character model(or anything else really, maybe some zombies?or a spaceship!) into Graw are five things(not counting, wit, the nessescary 3dsoftware and snacks)

- .diesel file

- model.xml

- materials.xml

- unit.xml

- textures

the diesel file, model.xml and materials.xml will all be in the same directory

for example data/objects/props/mysweetgun/

while the textures will end up the data/textures folder

and the unit file should be created in the /data/units folder or a subfolder of your choice.

this might look like alot of xml, but both the materials.xml and the unit.xml is just a few lines of xml and really no work at all!

And once you get the hang of the model.xml and realize how much you can do with it with just copy/paste/rename, you are

gonna have alot of fun with it!¨

lets get cracking!

The Diesel File:

The .diesel file is the file that contains the actual 3d geometry and other jolly good information that the game engine needs to properly set up and render your object.

This file is generated when you export your 3dsmax scene with the Diesel exporter that you should have in your “tools” directory in the root of the game folder.the exporter is currently only for 3dsmax 7.

The diesel file contains, 3d geometry, billboards(for trees, lightcones, etc), material names to be used in conjunction with the materials.xml file, lights, animations etc etc,

Also, GRAW uses the metric system(comon people, its 2006, maybe its time to join the rest of us in the glorius party that is the metric system)

and uses real world scale. So you need to change your 3dsmax settings to meters and centimeters.

One object that almost every diesel file should contain, is the “root_point” the “root_point” is a dummy box and is the local point from wich the object is spawned in the world. The “root_point” should be at the top of the link hierarchy in 3dsmax when you export.

The Model.xml:

Model.xml might actually be a bit misleading as the name of the model xml file could be anything from aardvark.xml to zebra.xml, it really doesnt matter but. Its usually nice though if it corresponds to the name of the other files so incase you have a .diesel that is named

“mysweetgun.diesel”

its nice to have a model.xml that is named

“mysweetgun.xml”

do you follow me? Its just so that it will be easier for you to keep track of your files.

the model.xml is called the model xml because it contains alot of information about your model(the one in the .diesel, remember?).

things suchs as, collision, damage models, decals, physicsconstrains, etc etc are all set up in this file. Also it tells the game wich .diesel and materials.xml file to use for the model. And this brings us to....

The Materials.xml

The materials is simply enough a little file that tells your dieselfile what shaders and textures they should use with wich corresponding material name in your 3dsmax scene.

So if your “mysweetgun” model in 3dsmax has a material on it thats called “mysweetgun” you specify that, what shader to use with that material and what textures to use in that shader.

No other material options than the material names in 3dsmax will be of ANY importance at all after you have exported it.

All the material handling is done in the materials.xml

The material file is always called materials.xml in GRAW but you can really call it whatever you want, but its nice to know that it contains materials!

A simple example of such a file could be

<materials>

<material name="mysweetgun" src="diffuse">

<diffuse_texture file="mysweetgun_df"/>

</material>

</materials>

if you have more than one material in your scene/object, just make another <material> tag after the first and repeat.

If you want to see more examples, just open of the many many material files that already excists in your unbundeled game directory!

“material name” is the name of the material in your original 3dsmax scene

“src” is the name of the shader, in this case just a standard diffuse shader

“mysweetgun_df” is the name of the actual texture file to be used in that shader.

The “df” at the end is just for your own sake so you can keep track of what kind of textures you have.

In GRAW we use “df” for diffuse, “bm” for normalmaps(normalbump) and “il” for self-illumiation textures, etc etc

But these are just optional, however it is a recommendation to use them if you want others to be able to use your textures in the future.

The Unit.xml

The unit xml is the end of the road for most models and its also the file that tells the game where to look for your model.xml , what to do with it, and what kind of object it should be, be it a prop, a static, a plant, etc. Its also the file that tells the editor to show the object in the object list so you can place it.

The name of the unit file should be u_mysweetgun.xml (where “mysweetgun” ofcourse can be anything your heart desires, but once again, its nice if it atleast resembles the name of the other files that you have created)

An example of such a file could look like this

<units>

<unit type="prop" name="mysweetgun" slot="13">

<network sync="bodies" />

<model file="\props\mysweetgun\mysweetgun.xml"/>

<script_class name="base" class="Base"/>

<stats block="base_data">

</stats>

</unit>

</units>

what this file tells us is that this object is a “prop” in the slot “13” that means that it will be displayed in the “props” layer in the games editor.

It tells us where to find the model xml to use for this “unit” and that it should be lightmapped ( more on this later as it involves both the materials and the model xml aswell)

It also tells us this

<xi:include href="/data/units/mass.xml#xpointer(/mass/mass_object_small/*)"/>

Which is coder mumbojumbo for “if you want to have alot of these objects in your map, you might want to add this to make it render faster”. It has to do with instancing and lodding of the objects, dont get me started.ask someone else.it works and its easy to add, so why not just add it?

You can exchange the “small” at the end, for “large”, “medium” or “big gulp(no, not really)”, depending on the physical size of the object. A gun for example, I would consider a “small” object, while a car might be a “medium”. But look in other unit files for examples of this.

Textures

For optimization issues, GRAW uses texture “texture atlases”

An atlas is a big texture, consisting of many smaller ones, baked into one, allowing faster handling in the engine. This is a matter of optimization and it reduces the number of texture switches for each object and therefor makes the objects faster to render.

To create such a “texture atlas” with your own custom textures in it, you will use the atlasgen.exe found in the tools directory together with the 3dsmax exporter. It is a command line program to be used in the command prompt of windows, but we will hopefully bundle a tool for you in the July-patch to make it more graphical.

However, its not that difficult to use for a beginner but has loads and loads of options if you are a more advanced user.

Graw uses the DDS format for textures.

Dxt5 for diffuse textures and a8l8 for the normalmaps.

That should be it for now, more indepth tutorials on each of the files will come with some practical examples on how to get objects, terrains etc into the game; step by step, from start to finish!

Happy modding

/the grin team J