Bullet Penetration and Ricochet Mechanics
Asset Properties Certain assets need to have the ability to be denoted by the level designer as "not penetrable." The Following assets will have a "Not Penetrable" property added to them in the Unreal Editor: • Individual BSP faces • StaticMeshActor • Material Bullet Penetration Rules Every material has two attributes: Damage Reduction and Deviation. Damage Reduction reduces the damage a bullet does per inch of material it passes through. Deviation determines how much the bullet changes direction per inch of material it passes through. These effects are determined by the total thickness of the material. When a bullet impacts a material, the thickness of the material will be determined. The damage reduction based on material thickness is applied to the bullet. If the bullet can still do damage, then it will penetrate the material. When the bullet exits the material, the deviation is applied to the bullet’s direction to determine its new path. A round will not penetrate any item that is over 15 inches (20 Unreal Units) thick and will not penetrate more than three surfaces regardless of material type and thickness. Examples with 5.56mm Round: • 1 inch Dense Metal door: by default, the round will not penetrate the material. • 4 inches of concrete/brick: damage reduced by 120%, does not penetrate, no deviation • 2 inch hard wood door: damage reduced by 10%, deviates 10 - 14 degrees. • 2 inch Drywall on each side: damage reduced by 4%, deviates 2 - 6 degrees Ricochet Mechanics Each individual bullet has 15% chance to ricochet off dense metal, mud brick, stone/ceramic tile, and concrete/brick. The base ricochet angle is the opposite angle of impact. The final ricochet angle is a random angle anywhere within that angle of impact in both Y and Z dimensions. This allows a bullet to ricochet up or down from its original path. A bullet will only ricochet if it hits a surface within 15 degrees of the material plane, and it can only ricochet off a maximum of three surfaces. Penetration Tables by Round Type 5.56mm Round Material (per inch) Damage Reduction Flesh/Organic 12.5% Concrete/Brick 30% Fabric/Cloth 2% Metal, Dense N/A Metal, Thin 7% Mud Brick 25% Paper/Cardboard 3% Plastic 3% Rubber 2% Wood, Natural 5% Wood, Hard/Processed 5% Tile, Stone/Ceramic 30% Plaster/Drywall 2% Glass 0% Sand 17% 5.56mm Match Ammo Material (per inch)