Setting up the project

The material and textures associated with the zombie_m model are currently located within the FBX_Imports folder. We will move these into different folders to organize them within the hierarchy of our project:

It may not be immediately visible within the Scene view due to the default import scale settings.

We will take care of this in the next step.

Unity's import settings can be adjusted to account for the different tools commonly used to create 2D and 3D assets. Import settings are adjusted in the Inspector panel, which will appear on the right of the unity interface by default:

The zombie_m character should now be visible in the Scene view:

This character model is a medium resolution model—4410 triangles and has a single 1024 x 1024 albedo texture and separate 1024 x 1024 specular and normal maps.

The character has been rigged with a basic skeleton. Creating a skeletal rig will be discussed in detail in the next chapter. The rigging process is essential if the model is to be animated.

We need to save our progress, before we get any further:

Despite the fact that we have only added a single game object to the default scene, there are more steps that we will need to take to set up the character and it will be convenient for us to save the current set up in case anything goes wrong.

In the character animation, there are looping and single-shot animation sequences. Some animation sequences such as walk, run, idle are usually seamless loops designed to play back-to-back without the player being aware of where they start and end.

Other sequences, typically, shooting, hitting, being injured or dying are often single-shot animations, which do not need to loop. We will start with this kind, and discuss looping animation sequences later in the book.

In order to use Mecanim's animation tools, we need to set up the character's Avatar so that the character's hierarchy of bones is recognized and can be used correctly within Unity.

Now that we have imported the model, we will need to adjust the import settings so that the character functions correctly within our scene:

Choosing the appropriate rig import settings

Mecanim has three options for importing rigged models: Legacy, Generic, and Humanoid. It also has a none option that should be applied to models that are not intended to be animated.

Legacy format was previously the only option for importing skeletal animation in Unity. It is not possible to retarget animation sequences between models using Legacy, and setting up functioning state machines requires quite a bit of scripting. It is still a useful tool for importing models with fewer animation sequences and for simple mechanical animations. Legacy format animations are not compatible with Mecanim.

Generic is one of the new animation formats that are compatible with Mecanim's animator controllers. It does not have the full functionality of Mecanim's character animation tools. Animations sequences imported with the generic format cannot be retargeted and are best used for quadrupeds, mechanical devices, pretty much anything except a character with two arms and two legs.

The Humanoid animation type allows the full use of Mecanim's powerful toolset. It requires a minimum of 15 bones, and assumes that your rig is roughly human shaped with a pair of arms and legs. It can accommodate many more intermediary joints and some basic facial animation.

One of the greatest benefits of using the Humanoid type is that it allows animation sequences to be retargeted or adapted to work with different rigs. For instance, you may have a detailed player character model with a full skeletal rig (including fingers and toes joints), maybe you want to reuse this character's idle sequence with a background character that is much less detailed, and has a simpler arrangement of bones.

Mecanim makes it possible reuse purpose built motion sequences and even create useable sequences from motion capture data.

Now that we have introduced these three rig types, we need to choose the appropriate setting for our imported zombie character, which in this case is Humanoid:

1. In the Inspector panel, click on the Rig tab.
2. Set the Animation Type field to Humanoid to suit our character skeleton type.
3. Leave Avatar Definition set to Create From This Model.
4. Optimize Game Objects can be left checked.
5. Click on the Apply button to save the settings and transfer all of the changes that you have made to the instance in the scene.

This is how the screenshot will look like:

Tip

The Humanoid animation type is the only one that supports retargeting. So if you are importing animations that are not unique and will be used for multiple characters, it is a good idea to use this setting.

In the next step, we will define the hierarchy of the joints in the Avatar.

Creating the Avatar

The Avatar Mapping settings allow you to specify how the bones relate to the model. You can think of the Avatar as an intermediary device that translates between the character model and the animations. It will dictate how motion will be transferred to the model, so it is important that all of the models bones are correctly identified within the hierarchy.

1. In the Inspector panel, click on the Configure... button to bring up the Avatar Mapping settings.

   Unity will prompt you to save your scene, which is necessary because the Avatar definition is actually done in a separate, temporary scene.

2. Click on the Save Scene button.

   The Avatar Definition panel will become active in the Inspector panel.

   The Mapping tab should be active by default. This shows a simplified diagram of a humanoid bone hierarchy. Beneath the diagram is a list where bones are selected.

3. Choose the Mapping rollout in the bottom left of the panel.
4. Click on Automap, Unity will attempt to assign the bones to the slots in the Avatar based on their names and position within the hierarchy.

Because our character's skeleton uses recognized naming conventions, Unity should have automatically put each bone into the right slot within the mapping definition. Any unidentified positions will show up in red, and any non-essential or optional bones that have not been identified will be displayed in gray.

Above the actual bone definition slots, there are alternate tabs for the body, head, left hand, and right hand, where more joints can be defined for more detailed rigs. With the exception of the head and neck, the bones covered under the Head tab are not that important right now. Facial animation will be covered later, in Chapter 6, Talking Heads.

The rest of the bones in the list for body, left hand, and right hand will need to be allocated. You can scroll down in the panel to see the names of the bones from your hierarchy and which position they have been placed in within the Avatar.

Tip

Note that the Avatar mapping definition only has two positions available for spine bones, if the character you are mapping has more than two bones in its spine (like this example), you can decide which of them to use.

I usually leave out the upper-spine bone, as it typically contains very little data in animation sequences, and because of its proximity to the neck and shoulders, which usually have more influence on the vertices of the model.

A common occurrence at this point of the process is a red warning display in your Scene view notifying you that the character is not in T-pose:

This is a simple fix, as we will demonstrate in the next step.

Adjusting the character's pose

Mecanim requires character models to be in a T-pose for them to be properly processed. The true T-pose is not a universal default pose for character models, and luckily Mecanim has a way to accommodate this:

1. Click on the Pose rollout at the bottom of the Avatar Mapping tab within the Inspector panel.
2. Choose Enforce T-pose. This will force your characters arms into a true T-pose so that they are Mecanim compatible.

   Note

   You may wonder why we don't just model a character in a T-pose rather than something more like an M. The main reason is that, while it is on the screen, the character's arms will usually be down by its side, modeling the arms at 45 degrees rather than 90 will minimize the amount of stretching of the mesh and textures.

Dedicated motion editing packages, such as Autodesk MotionBuilder, also require a true T-pose, so the Enforce T-Pose option within Mecanim is a good compromise and a nice touch, which saves us having to remodel or rerig a character in order to use these tools.

Checking the bone hierarchy in the Avatar

Mecanim's Avatar definition tools are responsive to bone hierarchy and naming conventions. If you are working with several character rigs that have the same bone names, it is likely you will only need to tweak the settings the first time.

The tool sometimes goes wrong. When this is the case, make sure you follow these steps:

1. Once you initiate the mapping process, the skeleton in your Hierarchy panel is expanded to make it easy to drag and drop. All you have to do is drag the bones from the Hierarchy panel into the appropriate slot in the list.
2. Take the time to check the bones in the list to make sure that there are no mistakes.
3. Optional bones, such as the neck and toes, are quite often left out by the automatic mapping, so it is a good idea to add them (in the appropriate definition slots), at this stage, before you apply the settings.

   Note

   If you make a mistake, just drag the correct bone onto the field in the list to replace it.

4. When you are finished, click on Done. This will save the settings of the Avatar and apply them to the instance of the model in the scene.

The Avatar asset will now be referenced in the Animator component of the character game object, which can be viewed in the Inspector panel:

At this point, our Avatar is configured, creating a link to our character's skeleton hierarchy that Unity can use.

Next, we will lay the ground work to add a simple animation that will run in the game.

States are the building blocks of the animator controller. Each state includes one or more motion clip. States are linked using Transitions, visually presenting the order in which states will become active:

Next, we will add the appropriate animation clips to the states:

These animations are now tied to the states that we have set up.

At the moment, the states are unconnected. To connect them, you need to create a parameter that will define the conditions that cause the character to switch to another state.

In the Animator interface, parameters are used to specify when states will run. They are similar to variables in Unity scripts and can take the form of integers, floats, and booleans. To create a parameter follow these steps:

This trigger parameter will determine when the zombie's attack animation will play.

The next stage is to create transitions between your two states. Transitions show how states are connected in the Animator window:

The transition is displayed as a white line with an arrow indicating its direction:

We also need to create a transition from Hit back to Idle, so the character will stop playing this animation:

As we want the full attack animation to play out, we will leave the Conditions box in the return transition with its default setting Exit Time. This will set the state to transition out once the animation has played through:

The Animation controller is now complete. We will add it to the male zombie character in the next step:

At this stage, when we test the game, the zombie will run its idle animation, as its Idle state is currently specified as the default state (marked in orange in the Animator window).

In order to enable the Hit state to take over, we will need to do a little scripting.

The character requires a small amount of code to enable it to switch to its Hit state and play the zombie_hit animation:

If any errors appear in the console, be careful that you have not left out any semicolons (that should end all operations and variables) or curly brackets (that should start and end all functions and statements).

This is a pretty short, simple script. We will be elaborating on this later in the book.

We need to add the script to the zombie character. This can be done by dragging the script from the Project panel onto the zombie_m game object in the Hierarchy panel to attach it as a component.

Next, we will make a few small adjustments to the scene, to make it easier to view our animation.

Now that we can clearly see the character within the view, we can test the animation:

This will cause the hit animation to play once before transitioning back to the Idle state.