Projectile System

Projectile System

Projectile Actor Creation

Basic Projectile Components

Create a new Actor_Projectile blueprint with essential components:

Core Components

• Sphere Collision: Root component for physics and collision
• Static Mesh Sphere: Visual representation (attached to collision)
• Projectile Movement Component: Handles physics and trajectory

Component Configuration

• Sphere Scale: 0.5 for all axes (smaller visual projectile)
• Sphere Collision: Custom collision, ignore all, overlap pawn only
• Static Mesh: No collision, no overlap events (visual only)
• Projectile Movement: Initial speed 1000, max speed 1000, gravity scale 0

Movement Settings

Configure projectile physics for different projectile types:

• Standard Projectiles: Gravity scale 0 for straight-line travel
• Grenades: Gravity scale 1 for arcing trajectories
• Arrows/Bolts: High speed (3000) with minimal gravity

Projectile Hit Detection

Collision System

Implement hit detection for projectiles:

// Projectile Hit Detection
OnProjectileHitboxOverlap(OtherActor) {
if (OtherActor != Owner) {
if (IsChildClassOf(OtherActor, Character)) {
Interface_Health_Modify(OtherActor, Subtract, Damage);
StopMovementImmediately();
SpawnVFXAtLocation();
DestroyProjectileAfterDelay(0.2);
}
}
}

Environmental Collision

Enable projectile interaction with environment:

• World Static: Allow collision with static environment objects
• World Dynamic: Allow collision with moveable objects
• Hit Registration: Projectiles stop and spawn VFX on environmental hits

Spawning System

Projectile Spawn Function

Create reusable function for spawning projectiles:

F_Spawn_Projectile Function

• Skeletal Mesh Input: Source mesh for socket location
• Socket Name Input: Spawn location socket
• Forward Offset: Distance in front of character to spawn
• Damage Input: Damage amount for this projectile
• Speed Input: Projectile travel speed
• Gravity Input: Gravity scale for trajectory

Spawn Implementation

// Projectile Spawn Logic
F_Spawn_Projectile(SkeletalMesh, SocketName, ForwardOffset, Damage, Speed) {
spawn_location = GetSocketLocation(SkeletalMesh, SocketName);
spawn_direction = GetActorRotation().ForwardVector;
offset_location = spawn_location + (spawn_direction * ForwardOffset);

SpawnActor(ProjectileClass, offset_location, GetActorRotation());
}

Montage Notify Integration

Control projectile spawn timing through animation notifies:

• Notify Name: “projectile_spawn”
• Timing Control: Spawn projectile at precise animation moment
• Animation Integration: Add notify to all projectile-based attack animations

Weapon-Specific Implementation

Magic Projectiles

• Socket: S_Right_Hand_Item
• Speed: 2000 units for medium-speed magical projectiles
• Scale: Standard sphere size
• VFX: Magical impact effects

Rifle Projectiles

• Socket: Muzzle (pre-existing on gun mesh)
• Speed: 3000 units for high-velocity bullets
• Scale: Small bullet size (adjust X/Y/Z independently)
• Forward Offset: 5 units from muzzle

Bow Projectiles

• Socket: S_Arrow (custom socket on bow mesh)
• Speed: 3000 units for arrow velocity
• Scale: Elongated (X=5, Y=0.5, Z=0.5) for arrow appearance
• Trajectory: May include slight gravity for realistic arc

Grenade System

Grenade Projectile Setup

Special projectile configuration for area damage:

Grenade Properties

• Custom Rotation: Enable custom rotation input for arc trajectory
• Gravity: Gravity scale 1 for realistic throwing arc
• Explosion: Area damage on impact
• Timer Detonation: Alternative to impact detonation

Grenade Throw Implementation

• Launch Angle: X rotation 22.5 degrees for throwing arc
• Custom Rotation: Override normal forward direction
• Speed/Gravity Balance: Adjust for satisfying throw feel

Projectile Polish

Visual Effects Integration

• Impact VFX: Spawn particle effects on hit
• Trail Effects: Optional trail particles during flight
• Environmental Integration: Ensure landscape generates overlap events

Performance Optimization

• Cleanup Timer: Destroy projectiles after set duration
• Collision Disable: Turn off collision after hit before destruction
• Visibility: Hide projectile mesh after impact while VFX plays

Team System Integration

Prepare projectile system for team-based games:

• Team Variable: Expose team assignment on spawn
• Friendly Fire: Prevent damage to same-team characters
• Owner Exclusion: Prevent self-damage from own projectiles

The projectile system provides flexible, reusable ranged combat mechanics that integrate smoothly with animation timing and visual effects while supporting multiple projectile types and behaviors.