This article will be a general overview of the modeling and texturing process we go through here at Cornered Rat Software in creating some of the building models you see in game. In particular this time we will be going over the modeling of the farm house ruins recently added into the game.

First, the artists receive a ticket from our producer on what needs to be built. The next step is to start gathering reference from any number of sources. We have stacks of WWII books here at the office we comb through. We also do some searching on the internet and any other available sources we can get our hands on. Once I have a good idea of what we want to build, I sketch out a few ideas before I start to model the object. In this case, it was a replacement for the old farm house ruins that were old 2d alpha plane buildings. Since these are a replacement for the older farm house ruins, I had to keep within the footprint of the previous buildings. The first thing I did was import the old building file into my scene to make sure to mark out and keep within the same boundary areas of the previous models.  For this particular model I had 7000 triangle limit.

Working off the reference images of the destroyed buildings I’ve collected, I try and recreate that in my scene with as few triangles as I can while still keeping the same destroyed farm house silhouette.  While modeling, I also need to keep in mind that people will be using this building for cover, and so I’ve also added an upstairs to the farm house with debris so players can snipe from the second level.

Once I’ve got the main building down, it’s time to move to the secondary objects and props. This is supposed to be an old farm house that’s been destroyed so we need fences, sheds, maybe a few troughs for animals that grazed here and also a few trees.  The high resolution model will be seen from 0-75 meters.

Once I’ve finished modeling the high detail model, I then move on to texturing it. I have a limit of one 1024x1024 set of images for texturing of the farmhouse. Below are some of the textures I created for this model (scaled down to 3/4 size for the web).  A combination of our naming of the texture and placement on the collider model is how the game interprets sounds for the game, either shooting rock, wood, stone, and what type of ground you are walking on as well.

After all the textures are applied I am finished modeling the high level of detail or LOD model for the object. Our building models usually have 6 states of LOD’s. They have three LOD’s for each state, three for an undestroyed state and three for a destroyed state. Those three LOD’s consist of the high resolution model, the low resolution model and a third resolution called a collider state.  Since this model is just a ruin, I only needed to create three LOD’s for this model since it’s going to remain in the destroyed state.

The low resolution model for the farmhouse is going to be seen from a distance about 75 meters out to 1200 meters. For the low resolution LOD, I can go in and remove much of geometry I created earlier on the model. For this LOD we usually reduce the polycount of the model to about half of what we have for the high poly LOD, so in this case we try to get it around 3500 triangles.

Now that we have two of our LODs done it’s time to build our collider model. The collider model is what you come into contact with in the game world.  Due to game engine and PC requirements, we need to break up our collider into chunks of 500 triangles or less and also break them up into sections. This is so when you are walking on the left side of the farm house ruin, you aren’t colliding against the far right hand side of the model and only colliding against those objects close to your character.  This LOD is an invisible copy of the model broken down in sections with fewer triangles then the high resolution model, but still possibly more then the low poly model, just due to what ever is needed in the model to collide correctly with the player. 

There are quite a few things we have to do internally using the FlightStudio plugin within 3dsmax in regards to naming and tree structures to get the model in game.  Once we get all this completed, we can then check it out in game. Many times there are issues and we’ll need to go back and tweak the buildings, issues with clipping and playability are accessed and fixed as needed.  Here is a screenshot of the model in game:

I'm currently applying this procedure to more of the buildings in the game world. The new loading dock is looking great and I'll continue working on replacing as many of the old 2d alpha plane buildings as I can get to.