How to Create a Character for Overgrowth

From Wolfire Games Wiki
Jump to: navigation, search


THIS IS A ROUGH DRAFT! It is not perfect, and is undergoing refining and polishing. This is also not a tool or code specific tutorial. Although you may not need to know alot before hand, this page assumes that you can stumble along just like I did, and get through this process until I get all the kinks worked out.


Now that that's out of the way, I want you to make sure that you read the Disclaimer right above this sentence. So, you want to make a new character for Overgrowth, huh? Well, this page will hopefully assist you in achieving your goal, or at least nudge you in the right direction. This is not a tutorial about how to use the tools I used. I will simply show you my process, and provide hints.

The Toolbox



I use Blender 3D for modelling and working with skeletons when I make characters, but I specifically use the 2.55 beta release because that is what David used for the current scripts. I have not gotten the .phxbn import and export addons to function in the newer 2.5x releases, but I will work it. Blender does take a little time to get familiar with, but it is rewarding once you've gotten it under your fingers.

I use Sculptris for the clothes scultping and for painting textures onto my models. It works very well, and is extremely easy to pick up and use right off the bat. It is also free, and is distributed and developed by the company that produces zBrush, which is not free, but I've heard is more advanced than Scultpris.

I use PaintdotNet to mix color maps and detail maps for the textures.(More on that later) It is free, and very easy to use. Although it isn't as great as Photoshop, I've stuck by it because it comes close to Photoshop's capabilities.

I use Notepad ++ for script editing, which is free and is also simple to use. Nuff said.

The Model

Before we get started, I reccommend keeping all of you character's new files in a folder until we add them to Overgrowth.

We can't have a character without a model, now can we? I use Blender because David has provided us with some fancy scripts in the Overgrowth releases that allow us to import and export our very own skeletons and animations out of and into the Pheonix Engine. These scripts are located under Overgrowth\Data\BlenderScript\addons (at least for now). The folder io_phxbn contains the files necessary to work with the Pheonix Bone(.phxbn) file format for skeleton rigs in Blender. The io_anm folder is used to import and export animations using Blender.

Although I'm not going to tell you what your model should look like, or how to go about building it, you need to know about a couple of things.

First, that unless you intend to create a whole new set of animations, which is possible, I would advise you to make your character's anatomy similar to that of any of the current functioning characters so that you can use the old animations on the new characters. So, if we make a giant spider, we'd have to make a new running animation, a new jump, crouch, ledge hang, and attack and so on and so forth. I have not tried to create a new set of animations, but I may in the future, and will post a tutorial on it.

We also have to remember that this is a game and that games, especially unoptimized ones, don't work well with high poly models, (Models with a large number of polygons) so we have to keep it reasonable. I compare to some Overgrowth character models when I want to keep the polygon detail similar between existing characters and the new ones.

Although a tutorial may be made on basic character creation, I'm not going into detail until the rest is finished.

So, now you've got your character modelled and ready to rig, but wait! How do we rig it for Overgrowth? David uses his own, epic file format. You're going to need Blender (2.55 until I test this on other 2.5x versions) for this part. When you install Blender 2.55, I reccommend installing somewhere other than where normal Blender is installed, and when prompted where to install user data files, select "Application Directory" so that the files are with Blender. Go to Overgrowth/Data/Blenderscripts/addons and copy the io_phxbn folder. Now, go to you Blender installation directory. Paste io_phxbn into Blender/2.55/scripts/addons. Now when you run Blender 2.55, go to user preferences, and open the Add-ons tab. Find Import/Export Pheonix Bone(.phxbn) and make sure that this addon is enabled. Save as default, and now we can export our new rigs, and import existing .phxbn rigs. Export your character to .obj file format.


I used Sculptris for modelling the clothing onto the nude character. The biggest reason I had for doing this was that Sculptris increases poly count as you need it, where you need it. So rather than having to edit the shape manually or use other methods, we can sculpt them on to our existing character. After we've opened up Sculptris, we'll need to get our model. Import the .obj file, and if it asks to go to paint mode, tell it no. When Sculptris brings you model up, find the symmetrical button. It's a box with a two-way arrow on it. If your character's base model is to be non-symmetric, don't hit this. If you want to make sure your base model is symmetric, or want symmetric clothes, then turn this on. Now that it's on, if you're going to have symmetrical clothing, leave this on. Otherwise, turn it off. All that did was set it to x-symmetry, that way both sides match up. If you keep it on, as you sculpt the same thing will happen to both sides of the character. If you turn it on and then turn it off, you will have a symmetric model that can then have non-symmetric details added.

I like to have a concept to look at before I begin adding clothes. It helps to keep in mind what you wanted, and how it should look. It also gives you a chance to decide that you don't like that idea after all. Use the inflate and draw tools to add volume and shape. You adjust the slider up top to change how many faces get created as you sculpt. I find that this wasn't tuned to fit game models well because it either adds no new faces, or it adds too many, no matter how careful you are with adjusting the detail slider. This means that you'll be working with the existing vertices more often than adding new ones to create the proper shapes. You can add these faces as needed in Blender, but Sculptris doesn't have a live update feature, so it's possible, but it would be painstaking.

Like modelling your character before, I'm not going to force a certain method on you. When making belts, try to keep them following a line of vertices, even if it's just a loose path. It will help to define the shape before we go to texturing. You can also use Sculptris to paint bump maps, although I haven't figured out how to use these as normal maps yet. These will help to give even better details, as it paints the light on a low resolution model using a texture to change how the light is drawn. In effect, it can distort light on a surface to look like it is more detailed than it is, and is a useful method to create better looking, but still efficient models.

Experiment with Scupltris to get a good feel for its controls, and sculpt your clothes on. Remember that this is no supposed to look like a finished product yet: It will only be the shape of you model, you can use the painting to get it to look much better.

The Rig

Go to Overgrowth/Data/Blender Files and open an exisiting character's rig. I like to use Turner's for characters of similar size and shape. If you are making a big character, or a canine, or a long tailed, short eared character, open the wolf's rig file. If not then open one of the others and see which one's skeleton is most like your character. For now, this means rabbits and wolves, but more will be added as Overgrowth is developed. Select the skeleton, and look in the right panel (Default Layout). Open the tab that has a little stick figure on it, spread eagle. There should be a set of four blocks of boxes. In the top right block, click the box in the bottom row, third from the right. Now, all we should see is the model, and the plain skeleton. Select the current character model, and delete it. Import your character's .obj file, and select the skeleton. In the right panel, go to the same little stick figure tab, and find the two boxes marked Pose Position and Rest Position. Hit the Rest Position button.

With the skeleton selected, go into Edit Mode. Move the balls of the bones around to change the skeletons shape to fit your character. Once that's done, go into Object Mode. Deselect everything. Select the model, and then Shift+Select the rig (Default Button Controls). Press Ctrl+P and select "Armature Deform" --> "with Automatic Weights". That should rig your character to the skeleton. Selecting the rig, change the setting under stick figure tab from Rest Position to Pose Position. Now your character should go to an animation if the .blend file you opened had one preloaded. Look you character over and see if you can spot any errors. These may include, but are not limited to unwanted spiky things, unwanted distortion of body parts, and some parts missed by auto-rigging.

If these errors arise, then select the rig. Enter Pose Mode, select the model and then enter Weight Paint Mode. Select the bone that isn't weighted properly and change the weight painting on the mesh to get it right.

Now that your rig is done, and it has been weighted for your character, let's get it into the engine. Select you skeleton, then go to File-->Export-->Pheonix Bone(.phxbn). You will want to export to your desktop, or your resource dump for this character. This rig won't work alone, though. We'll need to write a piece of xml later on to get it working, but we need to get all of the texturing and such done first.

The Textures

There are a few ways to get your model textured. You can export a UV map from Blender and use a 2D painting application, but I'm going to cover using Sculptris for painting. We're going to use Sculptris to generate the UV texture by producing a detail map, and a color map, and mixing them in PaintdotNet. I'll also cover some basics with normal maps and where I plan to go with those.

The Detail Map

Open Sculptris and import your model from its .obj file we exported earlier. If you're prompted to enter Paint Mode, then you have to check something. Is your character symmetric along the x-axis?

If the model is symmetric or you want it symmetric, but you want to paint the two halves individually, then don't go to Paint yet. Enter Sculpt and make it symmetric, then turn off symmetric, and proceed to paint.

If you have a symmetric model or want it symmetric and want it painted symmetrically too, then enter Sculpt and set it to symmetric. Proceed to Paint.

If you have an entirely non-symmetric model, then you can't use symmetry when painting: Go to Paint.

This is the part where you have to experiment with Sculptris' painting tool. You can choose a different material for display, which is fun to toy with. You can also disable material color, so that the materials color won't change how your painting looks. If you use the texture box on the top left, you can paint images onto your model. Sculptris has some good ones under its install location, inluding a good fur one. If you do use these, I reccommend dabbing like a sponge for clean, clear painting, and do short click-pulls for a finer, mor continuous look. With the fur texture, for example, dabbing pruduces tufty spots, but individual drags produces shorter, finer fur. Experiment with brushes and textures, but remember to keep this image greyscale. It's important that there is no color. And don't make the detail map too dark. If it's too dark, then your colors will come out blackened.

When you are detailing clothing, your lines don't need to be ultra clean. If they're blurred you can use the color map to make them appear more fine and clean. Once you've finished your detail map, open the advanced options menu near the top left, and save the texmap to your resource dump. Leave the detail map open on your model: it'll help with the coloring.

The Color Map

I'd advise disabling brushes and textures here. We only need to paint with solid colors. Paint over your detail map with the desired colors. Although they will be darkened by the greyscale detail map, we can adjust the brightness later. As you paint, keep in mind that clothes lines are often clean and defined, so do it here, if they were a little vague on the detail map. Natural lines like fur color shifts, stains, and such are a little blurrier. Again, you'll have to experiment with Sculptris to find how you like to work with it.

To Be Continued