Physical Animation: The Ultimate Starter Guide [UE4/UE5]

The video begins with an introduction to physical animation, a technique that sits between ragdoll physics and keyframed animation, used in games like Grand Theft Auto and Red Dead Redemption. It's employed for effects such as hit reactions and simulating states like tiredness or injury. The tutorial aims to show how to implement this in Unreal Engine, starting with setting up a blueprint class for physical animation on characters.

The tutorial continues with a step-by-step guide on setting up physical animation. It involves creating a new blueprint class, adding a physical animation component at runtime, and assigning a skeletal mesh to be used by the component. A custom event called 'toggle physical animation' is created to simulate physics on specific body parts, excluding the pelvis to prevent the character from falling apart. The video also includes a sponsorship mention for Skillshare, promoting a course on communication skills.

This section covers how to apply physical animation profiles to characters and test the setup. The profile named 'hit reaction profile' is applied to simulate the character's reaction to being hit. The video demonstrates the character's animation transitioning into a ragdoll state when the 'R' key is pressed. The importance of not simulating the pelvis for stability is reiterated, and the character's physical state is adjusted for testing purposes.

The video delves into the physical animation component's settings, such as 'set strength multiplier' for controlling the intensity of physical simulation. It's used to exit physical animation smoothly by increasing the multiplier to 10. The 'set all bodies below physics blend weight' function is introduced, which blends between keyframed animation and full simulation. The tutorial warns about the computational expense of using physical animation on multiple characters simultaneously.

The process of creating and adjusting a physics asset for a character is explained. This involves editing the collision capsules assigned to each bone to ensure they are appropriately sized and positioned. The video demonstrates how to use the physics asset to create more accurate bone collision detection in games. It also covers how to mirror adjustments made on one side of the body to the other for efficiency.

The tutorial shows how to mirror physics bodies to avoid redundant work and ensure symmetry in the character's physical behavior. It then focuses on setting up constraints for the physics bodies to limit their movement and rotation, preventing unrealistic flailing. The importance of accurate constraints for natural movement is highlighted, with a focus on areas like the shoulders and clavicles.

The video addresses a common issue with mirrored bodies not aligning correctly and provides a solution involving rotating the bodies in world space. It then suggests testing the ragdoll physics in zero gravity to identify unnatural poses and make necessary adjustments. The process includes setting up constraints for a more realistic physical simulation.

This section discusses the importance of preventing overlapping bodies from colliding with each other to avoid unnatural movements. It demonstrates how to enable and disable collisions between different body parts effectively. The tutorial also explains how to set up self-collisions to prevent body parts from penetrating each other during simulation.

The tutorial moves on to configuring physical animation profiles, which dictate how bones simulate in response to physics. It shows how to assign a 'strong' profile to various body parts for hit reactions and how to adjust strength values for different effects. The video emphasizes testing the simulation with animations to ensure they hold poses well under physical influence.

The video provides a detailed guide on creating hit reactions using the physical animation component. It explains how to start ticking the component, apply a physical animation profile, and add impulse to the character upon being hit. The tutorial also covers blending the physics simulation with the original animation to ensure a seamless transition back to the normal pose.

The final part of the tutorial covers creating a ragdoll state with self-preservation, where the character instinctively protects themselves when falling. It also demonstrates how to implement a 'tired state' that affects all animations, making the character appear fatigued. The video wraps up with a summary of the three use cases explored and a reminder of the Skillshare offer for viewers.