Collision Damage in Game Physics
A force based damage model is useful when a game needs impacts to feel fair. It connects a physical hit to a health loss. The calculator above treats the collision as a short event. It then converts impulse, speed, or known force into a damage value.
Using Unity Collision Values
In Unity, Collision.impulse is often the cleanest signal. It is the total impulse applied to separate two colliders. Dividing that impulse by fixedDeltaTime gives an average force for the physics step. If impulse is not available, relative speed and effective mass can estimate the same effect. A direct force option is also included for custom controllers.
Mass, Force, and Contacts
The model starts with effective mass. When two moving bodies meet, the reduced mass keeps the result realistic. When one object is static, the moving mass is used. Next, the chosen method estimates collision force. The force is split by contact count when several contact points share the impact.
Thresholds and Protection
Damage should not start at every tiny bump. The threshold field creates a safe zone. Only force above that value becomes harmful. Armor and material absorption reduce the working force before scaling. This helps metal, shields, rubber, or padded characters behave differently.
Curve and Cap Settings
The exponent setting controls curve shape. A value of one gives a linear response. Higher values make strong hits much more dangerous. Lower values soften the curve. The multiplier adjusts the final level without changing the curve. The maximum damage cap prevents one physics spike from destroying gameplay balance.
Energy Bonus
Energy bonus adds another tuning layer. Force explains sharp contact. Kinetic energy explains heavy moving bodies. A slow heavy object may still deserve damage. A fast light object may also hurt. Mixing both values often creates better vehicle, weapon, and ragdoll results.
Practical Tuning
Use this tool as a design helper, not as a strict engineering verdict. Game damage is a balance rule. Real collisions include deformation, friction, solver settings, and frame timing. Test values inside the scene. Log impulse, relative velocity, and contact count. Then tune threshold, scale, armor, and cap until the result matches player expectations.
Testing Presets
For best results, record several common impacts. Compare gentle touches, normal hits, and extreme crashes. Save presets for characters, props, vehicles, and projectiles. Consistent presets make tuning faster during every playtest too.