Adding physics to a character and scene
Physics add extra liveliness to your creations in Adobe Character Animator. This tutorial shows how to add tags and behaviors to your artwork to create effects like collidable objects, dangling hair, and a rainfall particle system.
Published
1 Make collidable objects
Add tags to make objects collide.
Introduction
Adding physics in Adobe Character Animator CC creates interactive elements that can help add life into your scenes.
Previewing basic physics interactions in a scene
Open the example PhysicsBeginnerLesson.chproj file and in the Project panel inside the Completed folder, double click Scene 1 - Basic Physics.
This should open the scene in Record mode.
If you drag the red bar or the blue circle, you'll notice they collide with each other, as well as the green boxes and purple ramp.
The objects bounce off the sides of the scene and letting go of the red bar returns it back to his normal position.
If you click the Scene Refresh icon in the lower right corner of the Scene panel, the simulation restarts and you can briefly see an orange triangle that falls through everything.
Back to the Project panel, if we go into the Unrigged folder and double click Scene 1 - Basic Physics (Unrigged), we'll see the same scene without any of the physics working yet.
Preparing puppets for physics in rig mode
To start rigging, double click Puppet 1 - Basic Physics (Unrigged), which opens this puppet in Rig mode.
You can immediately see that all the parts we want to work with are independent groups with crown icons next to them.
This allows them to act as multiple independent elements instead of moving together in unison.
Using dynamic, collide, and draggable tags
Click the top-level puppet above your list of layers and you'll see Physics already listed under the Behaviors in the right column.
Any time you import a PSD or AI file into Character Animator CC, Physics is one of the behaviors that will automatically get added to your puppet.
In the Puppet panel, select the Circle group and scroll down through the Tags area on the right.
Under the Physics section, click Dynamic.
This does two things: first, if the Attach Style was set to Weld or Hinge, it automatically switches it to Free because we don't need this to be attached to anything else.
Second, Collide also gets automatically tagged because these two are commonly seen together.
A Dynamic tag means this artwork will be subject to the laws of gravity and a Collide tag means it can bump into other collidable elements.
We can also add a Draggable tag to let us move it around with the mouse or fingers on a touch-enabled display.
Let's test things out so far.
Return to Record mode by clicking it in the top Workspace bar and you'll notice the blue circle immediately falls and bounces on the ground.
But if we try to drag it, it stays in place instead of bouncing around as expected.
To fix, this we need to find the Dragger behavior on the right and change two things: switch After Move to Return to rest and reduce the Return Duration to 0.
Click the Scene Refresh icon and now, the circle can be dragged and bounced around the scene.
Configuring static and dynamic platforms
Return to Rig mode and Shift select all four squares.
Clicking the Dynamic tag will set all of these to a Free attach style and also add a Collide tag.
Now click the triangle, to make it fall but not collide with anything, click the Dynamic tag and then untag Collide.
To make the purple platforms stay in place but still collide with objects, select Static Platform in the Layers list and only tag it as Collide.
Finally, select the Dynamic Platform group, tag it as Dynamic, which should also auto tag Collide and add a Draggable tag as well.
Then scroll down to Behaviors in the right column,
Custom physics behaviors and fine-tuning motion
click the Plus button and add a new Physics behavior to it.
When you add a physics behavior to a group, it will follow those rules instead of the global ones in the top of a puppet.
The only thing we'll change here is under Collision, setting Return Strength to 50%, so it will always try to snap back into its original position.
If you return to Record mode, now the scene should be working just like the original example.
Feel free to play around with the parameters in the Physics behavior to change things like Gravity, Wind Strength, Friction, Bounciness and more.
Whether it's a character fallen into a stack of boxes, a baseball being thrown or an astronaut floating in outer space, physics are a great way to add dynamic elements into your creations.
What you learned: Make a scene of collidable objects
The Dynamic and Collide tags make independent groups subject to the laws of gravity and bump into each other.
Adjusting the Physics behavior parameters can change things like wind, gravity, and bounciness.
Adding a Physics behavior directly to a group lets you set specific rules for just one object in a scene.
2 Add dangle physics
Add dangle handles to enliven several character features.
Introduction
The Dangle tag in Adobe Character Animator CC is a great way to add secondary animations to your character, that sway and bounce along with your character's movements.
Open the example PhysicsBeginnerLesson.chproj file and in the Project panel, inside the Completed folder, double click Scene 2 - Dangle Physics.
This should open the scene in Record mode.
Previewing dangle physics and stiffness effects
As I move my head in the webcam, I'll notice a lot of extra movement to this character.
Her hat bounces, her hair swings back and forth and the drawstrings on her coat move as well.
If I adjust the Stiffness parameter under Dangle, inside the Physics behavior on the right to 100% or higher, these elements become a lot more rigid.
But if I reduce stiffness to 1%, they get really long and springy.
Back to the Project panel, if we go into the Unrigged folder and double click Scene 2 - Dangle Physics (Unrigged), we'll see the same scene without any of the physics working yet.
We just get a flat character.
To start rigging, double click Puppet 2 - Dangle Physics (Unrigged)
Preparing the character for dangle rigging
which opens this puppet in Rig mode.
To get a better view of my character, I'll drag over the zoom percentage to zoom in closer and then hold down the Spacebar while dragging to pan over and get her centered.
You can immediately see that this character has a lot of independent groups with crown icons next to them, because we want these elements to move on their own without pushing or pulling on other parts of the face.
Adding dangle handles for hair and drawstrings
Let's start by selecting the Smallhair1 group which is one of the triangle hairpieces on her forehead.
The green circle that appears in the middle is called the origin handle.
This is where the artwork will pivot from and where it's attached to other parts.
In the case of this hair, we want it to swing from its roots where it would be connected to the head, so we can track the origin handle towards the top of the shape.
When we do this, we can see the underlying artwork it's attaching to show up as green.
In this case, the character's head.
Now, select the Dangle tool from the far right of the bottom toolbar and add a new Dangle handle at the bottom of the hair.
You can think of Dangle handles as small metal balls which help determine where gravity will be pulling down on the artwork.
In this case, the tip of the hair.
Let's do the exact same thing to the other two small hair triangles.
Select one, move the origin handle to the top and then add a Dangle handle at the bottom.
Then repeat the process for the last one.
Because these elements have similar shapes and rigging, they'll all tend to move in similar ways, this same technique can be applied to the rest of the character.
For the two Longhair groups, move the origins to the top so they attach to the head and add Dangle handles at the bottom towards the tip.
For the two Drawstring groups inside the Body group, move the origins to the top, behind the Neck layer and add Dangle handles at the bottom.
Stabilizing larger elements with sticks and fixed tags
The Backhair group is treated a little differently, because this is one large group that has multiple strands combined together instead of a long narrow piece.
In this case, move the origin to around the forehead then use the Stick tool to draw a stick directly across it and tag that as Fixed.
This way, the top part of the hair will stick in place instead of coming unhinged and having the side swing out.
Then I can add multiple Dangle handles below to have gravity pull down on several parts of this larger artwork.
Customizing dangle behavior on individual parts
Finally, sometimes you might want one element to move a little differently than the others, like this hat.
So, I can select it, scroll down to the Behaviors on the right, click the Plus button and select Physics.
Now, the changes I make here will only affect the hat.
In this case, I'll just change the Dangle Stiffness to 50% to give it a little more bounce.
If I return to Record mode, I should see all the parts I've added Dangle handles to, now reacting to my movements.
Playing around with the Physics behavior parameters like gravity, wind and stiffness can make these reactions more or less subtle.
So, experiment with these in your own characters and see what looks best to you.
What you learned: Adding dangle physics to characters
A dangle handle is like a metal ball that causes character parts to bounce, sway, and slide realistically with your character’s movements.
Moving the origin handle of any independent group will determine where it attaches to other artwork and where dangle handles pivot from.
Adjusting the Physics behavior parameters, particularly stiffness, will make dangle effects more or less subtle.
3 Create a particle system
Make falling or shooting particles.
Introduction
Adding particles in Adobe Character Animator CC allows you to create interesting weather systems like rain and snow or projectile elements like cannonballs.
Open the example PhysicsBeginnerLesson.chproj file and in the Project panel, inside the Completed folder double click Scene 3 - Particle Physics.
This should open the scene in Record mode.
Previewing particle physics in action
Blue circles immediately start raining down from the top of the scene.
As you move your head, the umbrella character bumps into them, sending them bouncing onto the floor where they eventually fade away after a few seconds.
Meanwhile holding down the left mouse button shoots a larger droplet out of the green pipe in the upper right corner, which bounces off the umbrella and through the blue circle particles.
Back to the Project panel, if we go into the Unrigged folder and double click Scene 3 - Particle Physics (Unrigged), we'll see the same scene without any of the physics working yet.
Opening the unrigged scene and preparing for particles
To start rigging, double click Puppet 3 - Particle Physics (Unrigged) which opens this puppet in Rig mode.
Getting started with particles is easy.
Shift select Ball1 and Ball2,
Creating falling particle systems with the particles behavior
scroll down to Behaviors on the right, click the Plus button and select Particles.
I'm going to set the Particle Mode to Snow, which starts the simulation with the particles falling from the sky.
Then I'll drop the Particles Per Second to 5, change the Velocity to 250 px/sec and Spread to 50%.
These look good to me but you can adjust these parameters to whatever you want.
I'll make sure to check the box next to Collide.
You don't need any additional physics tags for particles.
I'll also check Fade Particle Opacity, so they gracefully disappear.
Because I want these two particle systems to be slightly different, I may then only select Ball2 and change a few things like Randomness and Particles Per Second.
Then, to make sure the umbrella will do its job
Making objects interact with particles using collisions
and keep the rain out, I'll select its group and simply give it a Collide tag.
Finally, to make the larger droplet into a cannon,
Building a cannon-style particle emitter
I'll select the Droppy group, add another particle behavior to it, change the mode to Cannon and make sure to check Collide.
I can also experiment with the parameters below.
I'm going to start with only 1 Particle Per Second and the Direction shooting out to the left, at about 270 degrees.
If I return to Record mode, now the circles fall down and bump into each other.
The umbrella moves with my head and collides with the rain and the larger droplet can be shot out of the pipe.
Colliding particles can add some fun effects into your scene and even small parameter adjustments can lead to completely different looking simulations.
See what works for your character and scenes and have fun.
What you learned:
Adding a Particles behavior turns any independent group into a falling sequence or a shooting cannon.
Checking Collide in the Particles behavior makes it collide with other objects, like rain bouncing off of an umbrella.
Changing behavior parameters like velocity and particles per second has dramatic effects on the simulation.
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