Physics Volumes

APhysicsVolume overrides physics properties for any actor inside. Common subclasses: KillZVolume, PainCausingVolume, WaterVolume (community).

Properties

Property	Effect
Fluid Friction	Damping for actors inside (used for water-like volumes)
Terminal Velocity	Cap falling speed
Priority	Higher priority wins on overlap
Water Volume	Marks as fluid; gameplay code can check Pawn->PhysicsVolume->bWaterVolume
Gravity Override	Custom gravity scalar — set to negative for inverted, 0 for zero-G

Default volume

Every level has an implicit DefaultPhysicsVolume (gravity from WorldSettings → Default Gravity Z, default -980 cm/s²). PhysicsVolume actors override per-region.

Water-volume pattern

void AMyCharacter::Tick(float DeltaTime)
{
    Super::Tick(DeltaTime);
    if (GetPawnPhysicsVolume()->bWaterVolume)
    {
        GetCharacterMovement()->SetMovementMode(MOVE_Swimming);
    }
}

Zero-G volume

Set Gravity Override = 0 and Terminal Velocity = 99999 for floating-in-space gameplay zones.

Combining with PostProcess

A physics volume usually pairs with a PostProcess volume covering the same region (underwater filter, color grading, audio reverb). Place both with matching bounds and matching priorities.

Gotchas

• Static physics volumes don't tick — actors check PhysicsVolume once on overlap entry.
• Replication of physics volume membership is handled by character movement; custom pawn classes need to forward the check explicitly.
• Multiple overlapping volumes resolve by priority but only one wins per actor.