Using ACTIVE RAGDOLLS for a realistic injury system in Unity

Summary

The video presents a prototype injury-reaction system built around active ragdolls—physics-driven characters that try to follow a hidden animated character. Instead of switching to ragdoll physics only for death animations, the creator uses the active ragdoll throughout character movement and interaction.

Active-Ragdoll Setup

The ragdoll follows the hidden character’s animation using physics forces. Early tests made the character excessively wobbly because its root bone was fixed. The creator allowed the root to fall by detecting when its angle exceeded a threshold relative to the world’s up direction, and considered leg rotations as an additional factor.

Injury and Condition Modifiers

The system adjusts the forces used to follow the animation through three values:

• Limb strength reduces force in an injured limb, making it clumsier. At zero strength, the limb can give way.
• Consciousness affects strength across all limbs. It can drop after falls, hard impacts, or blood loss, and may recover over time.
• Health decreases from bleeding and impacts. Low health also limits maximum consciousness, keeping the character impaired.

Weapons and Projectiles

To test the system, the creator added a weapon model, sounds, and firing effects, along with a weapon wheel for selecting and equipping weapons.

Bullets are affected by gravity and drag. On impact, the penetration system reduces their effectiveness and can alter their direction unpredictably based on their velocity.

The video is a development walkthrough and prototype test rather than a formal review. The creator plans to combine the injury system with procedurally generated worlds in later work.

Main speaker/source: The video’s creator, Nermin Bačić (channel: Nermin Bačić).