Hi, I’m Nicky! Welcome to my Channel about Game Development. This is a video in a series dedicated to learning
Unity’s animation system. In the previous video, we learned to give
players control over character animations using two dimensional blend trees. Today we are going to learn how we can retarget
animations from one character to another! Alright, let’s get started! At the start of this series, we learned to
download free characters and animations from a free adobe platform called Mixamo. We proceeded by learning to import, set up,
and control them in Unity! Let’s rewind back to our starting point. We’ll start by downloading a single jumping
animation from Mixamo with the usual settings, except this time we’ll add the skin and
export a different character than the one that we initially downloaded. If you are new to the series, any character
will do and feel free to use the settings on screen. Opening Unity, we’ll import this new character
and animation. Next, we’ll open up the asset store and
download and import two free additional characters: Jammo, which is the free mascot character
of the youtube channel “MixAndJam”. And “SpaceRobotKyle”, which is a classic
free character provided by Unity for download. In newer versions of Unity, we can download
and import these characters from the package manager. When importing Jammo, we’ll need to be sure
to deselect unnecessary folders. We really only need the materials, Models,
and Texture. Now to get everyone starting from the same
place, let’s start by adding Jammo, SpaceRobotKyle and our new Mixamo character to the project
hierarchy. If our projects are URP or HDRP, we will need
to upgrade the materials of our characters by pressing edit, render pipeline, universal
render pipeline, upgrade project materials to UniversalRP Materials. Additionally, our mixamo character may have
textures packed in the FBX file. To extract these materials, simply select
the character from the project tab, press Materials in the inspector and click Extract
Textures. Next, We’ll add animator components to each,
create a new animator controller titled “retargetController” and select this controller using the circle
selector. If you are starting from previous videos in
the series, you may have the original mixamo character from previous tutorials. For this character, we can remove the old
animation controller, disable any scripts and reuse the “retargetController”. Great! Now let’s begin by demonstrating how the
jump animation we just downloaded is not currently compatible with any of our characters outside
of the original character it’s attached to. Duplicating the animation, we’ll rename
the copy to testJump. Next we’ll add the animation to our retargetController
as a new animation state and set testJump as the default animation state. Entering play mode, we’ll see that our new
Mixamo character performs the jump, but the others don’t. But why? To get a better understanding, we can take
a look at the animation itself. If we open the animation tab, we’ll be presented
with… nothing. This is because we need to select either the
animation from our project tab or we can just select the characters in the hierarchy. Let’s select the working Mixamo character,
and we’ll immediately see the animation tab be populated with new data. In the left panel, we’ll see all of the
bones that are modified in the animation and in the right panel we’ll see the keyframes. Each key stores the changed parameter values
per bone for every frame. If we press on the preview button and press
play, we’ll see that the Mixamo character performs the animation! Great! Everything works as expected. Now let’s select any of the other characters. We’ll find that this animation currently
is incompatible with any other character. This is because the bones of our original
character do not match the bones that are modified in the animation. When looking at the bones in the animation,
Unity will tell us that each bone is “Missing”. And if we want to be specific, we will notice
the difference in this particular example is that the bones in the new animation all
have different names. So can we simply rename all of the bones in
our selected character’s rig in order to use the animation? Well this might work if the bone positions
are fairly similar between the characters. But if the character models have different
proportions, we end up with an unusable result like this. So what can we do to fix this? How can we share animations between models
that are seemingly very different? The answer is Unity’s avatar system and
humanoid rigs. We’ll start by selecting our imported character
in the project tab. In the inspector window, we’ll see four
tabs: Model, Rig, Animation and Materials. For today, we’ll just be using the “Rig”
tab. Selecting “Rig”, we’ll be presented
with new settings: “Animation Type”, “Avatar Definition” and “Skin Weights”. Let’s start from the top. We’ll notice when selecting the “Animation
Type” drop down, we have 4 options: “None”, “Legacy”, “Generic” and “Humanoid”. Selecting “None” will actually disable
the character’s rig, so it won’t animate at all. “Legacy” is Unity’s original animation
system from years ago prior to their purchase of Mecanim: which is the backbone Unity’s
current animation system. Unity’s documentation states not to use
legacy and that it’s simply there to support old projects that were already using that
animation system. “Generic” is what we’ve been using in
this series up to this point. It’s the default Animation Type when importing
character fbx files from Mixamo and Blender that include character rigs. And finally, we have Humanoid, which is Mecanim’s
solution for retargeting animations between “humanoid” characters. Typically, we might think of humanoids as
bipedal characters like humans, orcs elves, robots and aliens. Let’s select humanoid. we’ll notice that the “Avatar Definition”
setting is now set to “Create From This Model” and a new “Configure” button
is greyed out. This is one of the two selectable options:
the other being “Copy From Avatar”. These being the only two options, we now understand
that avatars are required for Humanoid Rigs. Pressing “Apply” we’ll see “Configure”
is now selectable. This will take us to a completely new menu
within Unity so before we press it, let’s cover the remaining settings. Skin weights are used to modify the vertices
of a mesh on a per-bone basis. In a 3D modeling software like Blender, we
are able to perform a process called “Weight Painting” where we designate which bones
will adjust selected vertices when the bone moves. When weight painting, we can have multiple
bones impact a single vertice. For example, if we really wanted to, we could
have the toe bones control the head of our character. So taking this back to Unity, “Skin Weights”
has a default value of 4 bones which can control the vertices of the character mesh. but can
also be set to a custom amount if our model has vertices that are impacted by more or
less than 4 bones. Additionally, when custom is selected, we
can give it a minimum accepted influence amount so that bones that have less than a certain
percentage of control over the vertices won’t be included. Unity’s default value of 4 bones is to enhance
performance, so it is possible that if certain bones are neglected, a model may deform in
unexpected ways. Here are a couple of examples from the Unity
forums where developer’s meshes were deforming differently than they did in the modeling
software. Today we’re going to stick with the default
value of 4. And the last setting in this window is the
“Optimize Game Object” toggle which is another setting that appeared when switching
to humanoid. This will remove the transform hierarchy from
the imported model and essentially bake it into the avatar and animator component. It’s recommended in the docs to apply this
before shipping the final product, but I did notice that if we have an animator component
already attached to our character in the scene hierarchy, our character will disappear. Be sure to apply this setting without an animator
attached or you will need to remove the character and add the prefab back to the scene. For now, we will leave the optimization unchecked. Awesome! We now have a solid understanding of all of
the Rig settings. Pressing “Configure” we’ll see a completely
new menu in the inspector and our scene view transforms into an isolated view of our character. In the inspector, we’ll be presented with
an outline of a humanoid character with small circles at designated parts of the body. And below, we’ll see a list of body parts
associated with each circle. The dotted circles are considered optional. When first configured, Unity will attempt
to auto-map each bone from the character rig to its corresponding bone in the list by searching
for specific names and abbreviations that match. When using characters from Mixamo or one of
the many humanoid characters downloadable from the Unity asset store, it’s more than
likely that the auto-population will have each matching bone properly sorted when first
entering this screen. This is why the list is already filled out! However, if we make our own characters in
a 3D modeling software such as blender and have different names for our bones than what
Unity is expecting, we’ll instead be presented with a red character outline. And the list will have empty selectors that
we’ll have to go through and map ourselves. For more complex characters and animations,
we also have the options to map bones associated with the head, and both left and right hand. All of which are optional. At the bottom of the list, we’ll see two
dropdown menus titled “Mapping” and “Pose”. Mapping has 4 options: “Clear”, “Automap”,
“Load” and “Save”. Clear will remove all paired bones. And automap will search through the list and
pair associated bones found in the character rig; the same function that is performed when
we first configure the humanoid avatar. Again, this only works if Unity can find the
bones by name. Load and save allow us to save and reuse our
list of mapped bones. This would be useful in situations where the
automap failed, and after we finished manually mapping the bones on one character, we could
save and then load that mapping for other characters with the same bone names. The pose dropdown has just 3 options: “reset”,
“sample bind pose” and “enforce t-pose”. When the humanoid is first configured, if
the automapping of the bones works as intended, Unity will automatically apply “enforce
T Pose”, which is what we see here. If we press “reset”, the character will
shift its bone transformations back to the starting frame of the animation attached to
the character, or the rest pose if the character doesn’t include any animations. And lastly, “sample bind pose” will reset
the character’s bone positions back to the character’s bind position. The bind position is the position the character
mesh was in when initially binding, or connecting, the bones to the mesh. The binding process is done inside of a 3D
modeling software and the bind pose is hidden and stored in the FBX file. Any changes we make in this menu will need
to be applied before pressing Done to exit out of the avatar configuration process. Before we move on, we have a second tab titled
“Muscle and Settings”. This menu is for modifying the muscle constraints
our character currently has. We can preview these constraints and how they
impact the possible range of motions for our character by moving the sliders around in
each column and row. If we want to adjust the constraints, we would
do so in the Per-Muscle Settings and Additional Settings and press “Apply”. The muscle settings are typically used when
converting models from generic to humanoid that have exaggerated character meshes. For example, a character with massive arms
might experience clipping where a smaller character would not. We can adjust the constraints of the muscles
to limit the bend in the arms and reduce any visual issues! Ok! Now that we’ve completed a breakdown of
Unity’s humanoid rig setup, how does this help us? The answer is quite simple: when we convert
the character to humanoid, this process generates a humanoid “avatar” storing the new bone
hierarchy that is interchangeable with other humanoid avatars! It also converts any animations that are included
in the character FBX file from generic to humanoid meaning any humanoid character will
be able to use this animation! Let’s go ahead and create humanoid avatars
for all of the newly downloaded characters. Once completed, we’ll select each of our
characters in the hierarchy, and using the circle selector in our animator component,
we’ll match the newly created and corresponding avatar! Pressing play, we’ll now see some possibly
unexpected results. Now none of our characters are jumping. This is because we duplicated the jump animation
before we switched to humanoid rigs so that animation is still tied to the old bone hierarchy! So the last change we’ll need to make is
to duplicate the animation one more time from the now humanoid version of our mixamo character. This time we’ll call it “retargetJump”. We’ll delete the “testJump” and set
“retargetJump” as the default animation state. Pressing play and Vwalaha! We have retargeted our jump animations from
one character to another! Amazing Job! With what we just learned, a slight modification
to the scene, and a brand new animation: we can get an awesome result like this! Before we end today, there are a couple of
important notes. To start, if we download animations from Mixamo
without the skin, we still can and need to switch the Rig type to humanoid. When downloading these animations on mixamo,
be sure to have the same character selected as the one you used from this tutorial. This way, the animation FBX will have the
same bone names. AND we also need to select copy from avatar
and select our downloaded mixamo character’s avatar! Now these new animations will be usable with
our other characters Next, if you have been following along through
this series from the very beginning, you will need to switch the Rig type on all of the
animations in your animation states to humanoid if you want them to work with humanoid characters. If any animation in our animator have generic
animations, it will break the character’s animations. I recommend renaming the new humanoid copies
of the animations to avoid confusion. And when selecting the duplicate animations
we also want to change the “Root Transform Rotation” setting from “Body Orientation”
to “Original” and check bake into pose for our animations to look as expected. Lastly, if you are completely new to the series,
in previous videos we learned to control animations through player input. With the knowledge attained today about humanoid
characters, we can combine that with the teachings of previous videos and actually give players
control over any of our humanoid characters and animations! It’s RAD! Awesome work today! If you liked what you learned, please consider
pressing the like button and subscribing to the channel! It really helps the channel grow and tells
me that we’re covering content you care about! In the next video, we’ll learn to use animation
state layers and not long after, animation based events! If you would like to join a growing community,
I’d be happy to have you as a member of the channel discord! Link is in the description. But that’s all for today, thank you so much
for watching and I’ll see you in the next video!
