Grenade Asset — ItemThrowableAsset

Advanced45-60 minutesWindowsUnity EditorVisual StudioU3 SDK

Mastering throwable weapon mechanics in Unturned — from timed fragmentation grenades to sticky C4 variants, flashbang crowd control, and impact-triggered explosives — depends on understanding how ItemThrowableAsset inherits the weapon damage multiplier system while adding fuse timing, throw physics force values, and four explosive type flags that determine detonation behavior. ItemThrowableAsset inherits from ItemWeaponAsset, reusing the damage table infrastructure for explosive throwables. It defines grenades, flashbangs, sticky grenades, impact grenades, smoke grenades, flares, and other hand-launched projectiles.

Source code location: Unturned/Items/ItemThrowableAsset.cs

Inheritance Chain

ItemAsset
  → ItemWeaponAsset
    → ItemThrowableAsset

Inheriting from ItemWeaponAsset gives throwables access to playerDamageMultiplier, zombieDamageMultiplier, animalDamageMultiplier, range, and the BuildExplosiveDescription / BuildNonExplosiveDescription helper methods.

Throwable Prefab and Audio

Field	Type	Source
_throwable	GameObject	Bundle "Throwable" — the physics projectile
_use	AudioClip	Bundle "Use" — sound played on throw release

The throwable prefab is instantiated at the player's hand position and launched with Rigidbody.AddForce. It must have a Rigidbody and Collider. The prefab carries the appropriate throwable behavior component (Grenade, Flashbang, StickyGrenade, ImpactGrenade, etc.).

Explosive Type Flags

Four boolean flags define detonation behavior:

Flag	.dat Key	Description
_isExplosive	Explosive	Radial damage on detonation using weapon damage multipliers
_isFlash	Flash	Blind and deafen nearby players
_isSticky	Sticky	Attaches to surfaces on contact using OnCollisionEnter
_explodeOnImpact	Explode_On_Impact	Detonates immediately on collision, no fuse wait

Flag Combinations

Flags	Behavior
_isSticky | _isExplosive	Sticky grenade
_isSticky | _isFlash	Sticky flashbang
_explodeOnImpact | _isExplosive	Impact grenade
_isFlash only	Flashbang (no damage)
None	Smoke grenade or flare

When any of explosive/flash/impact is true, shouldFriendlySentryTargetUser returns true. Pure smoke/flare throwables are considered non-hostile.

Fuse Timing

fuseLength controls the delay between release and detonation:

Condition	Default
Custom Fuse_Length set	Parsed float value
isExplosive or isFlash	2.5 seconds
Neither (smoke/flare)	180 seconds (3 minutes)

The fuse timer starts on release, not on collision. Impact grenades ignore the fuse entirely.

Throw Physics

Field	Type	Default	Description
strongThrowForce	float	1100	Primary-throw force in Newtons
weakThrowForce	float	600	Secondary-throw underhand force
boostForceMultiplier	float	1.4	Sprint-throw multiplier

The throw trajectory:

1. Launch direction = camera forward + upward pitch offset.
2. AddRelativeForce(throwForce * direction, ForceMode.Impulse).
3. Spin torque for visual rotation.
4. Standard Physics.gravity affects the arc.
5. Boosted throws only while sprinting.

Explosion Parameters

Field	Type	Description
explosionEffectGuid / _explosion	Guid + ushort	Explosion effect reference
explosionLaunchSpeed	float	Physics launch velocity for blast impulse

The explosion effect is instantiated at the detonation point. DamageTool.explode(...) applies damage using:

• playerDamageMultiplier, zombieDamageMultiplier, animalDamageMultiplier, barricadeDamage, structureDamage, vehicleDamage, resourceDamage, objectDamage from ItemWeaponAsset.
• range as the blast radius.
• explosionLaunchSpeed for the physics impulse.

Explosion Damage Calculation

DamageTool.explode(new ExplosionParameters(...)
{
    playerDamage = playerDamageMultiplier.damage,
    zombieDamage = zombieDamageMultiplier.damage,
    animalDamage = animalDamageMultiplier.damage,
    barricadeDamage = barricadeDamageMultiplier.damage,
    structureDamage = structureDamageMultiplier.damage,
    vehicleDamage = vehicleDamageMultiplier.damage,
    resourceDamage = resourceDamageMultiplier.damage,
    objectDamage = objectDamageMultiplier.damage,
    range = this.range,
    launchSpeed = explosionLaunchSpeed,
});

Linear falloff from epicenter to range. Entities at exactly range take 0 damage.

Impact Behavior

ExplodeOnImpactDestroyOnClient (default false):

• true: Clients destroy the throwable immediately on collision (more responsive).
• false: Clients keep the prefab alive until server confirms detonation (backwards compatibility).

Impact grenades use collision velocity threshold: relative velocity > 1 m/s triggers detonation. Slow rolling along ground does not trigger.

Concrete Throwable Behaviors

Grenade (standard explosive)

• Attached when _isExplosive && !_isSticky && !_explodeOnImpact.
• Starts fuse timer on Start() after being thrown.
• On fuse complete: plays explosion effect, calls DamageTool.explode, destroys self.
• Bounces with configurable bounciness from the prefab's physics material.

Flashbang

• Attached when _isFlash && !_isSticky && !_explodeOnImpact.
• Full-screen white flash overlay with configurable duration.
• Loud deafening audio effect.
• Duration inversely proportional to distance from epicenter.
• Zombies within range are stunned for the flash duration.

StickyGrenade

• Attached when _isSticky && (_isExplosive \|\| _isFlash).
• On OnCollisionEnter: attaches transform to contact surface.
• Disables rigidbody gravity and sets isKinematic.
• Fuse timer continues after sticking.
• If parent object is destroyed, falls with gravity until next collision.

ImpactGrenade

• Attached when _explodeOnImpact.
• On OnCollisionEnter: immediately detonates.
• Fuse timer not started — instantaneous on collision.
• Used for rocket-propelled grenades and contact explosives.

The UseableThrowable Launch Sequence

1. Equip: Throwable prefab loaded from ItemThrowableAsset._throwable.
2. Pull pin: Left-click starts throw animation; fuse starts on release, not pull.
3. Aim: Camera forward determines trajectory.
4. Release: Prefab instantiated at hand position, AddForce(throwForce * direction), fuse starts.
5. Boost: Sprinting applies boostForceMultiplier.
6. Physics: Parabolic arc under Physics.gravity.
7. Detonation: Trigger behavior (fuse, impact, sticky) fires.
8. Cleanup: GameObject destroyed; explosion effect spawned.

Network Synchronization

Client: "I'm throwing a grenade at position X with velocity V"
Server: "Confirmed, start fuse timer. Result at T+2.5s"
Client: (predicts explosion at T+2.5s)
Server: "Grenade detonated at T+2.5s, all clients explode"

Server-authoritative timer with client prediction. Late-joining players see explosion if still playing but receive no damage.

Description UI

BuildDescription displays:

• "Flash" tag if _isFlash (green, DescSort_Important).
• "Sticky" tag if _isSticky (green).
• "Explodes on Impact" tag if _explodeOnImpact (green).
• Fuse length in seconds if explosive or flash.
• Explosive damage table via BuildExplosiveDescription if _isExplosive.

Safezone Restrictions

canBeUsedInSafezone returns false when safezone.noWeapons is true. All throwables blocked in weapon-restricted safezones. Non-weapon safezones allow throwables.

Prefab Requirements

Requirement	Reason
Rigidbody	Physics simulation for parabolic arc
Collider	Surface interaction (bounce, stick, impact)
TriggerGrenadeBase component	Detonation logic
Trail renderer (optional)	Visual arc in flight
Particle system (optional)	Explosion effect

Cargo Data Export

Writes to the Throwable Cargo table through its ItemWeaponAsset base.

Writes to the Throwable Cargo table through its ItemWeaponAsset base.

Worked Code Example: Custom Throwable Behavior

using SDG.Unturned;
using UnityEngine;

public static class ThrowableBehaviorController
{
    /// <summary>
    /// Creates a throwable with custom fuse time, overriding the asset's
    /// default fuse length. Useful for skill-based throwable modification.
    /// </summary>
    public static void ThrowWithCustomFuse(
        ItemThrowableAsset throwable,
        Player player,
        float customFuseLength,
        Vector3 direction
    )
    {
        GameObject throwableObj = GameObject.Instantiate(
            throwable.throwable, player.look.aim.position, Quaternion.identity
        );

        Rigidbody rb = throwableObj.GetComponent<Rigidbody>();
        if (rb != null)
        {
            float force = player.movement.isSprinting
                ? throwable.strongThrowForce * throwable.boostForceMultiplier
                : throwable.strongThrowForce;

            rb.AddForce(direction * force, ForceMode.Impulse);
        }

        Grenade grenadeComponent = throwableObj.GetComponent<Grenade>();
        if (grenadeComponent != null)
            grenadeComponent.Invoke("Explode", customFuseLength);
    }
}

Mermaid Diagram: Throwable Launch Sequence

Comparison: Throwable Types by Flag Combination

Flags Set	Class	Behavior	Fuse	Sticks	Damages Players	Damages Structures
_isExplosive	Grenade	Radial damage	2.5s	No	Yes	Yes
_isFlash	Flashbang	Blinding + deafening	2.5s	No	No (stun only)	No
_isSticky + _isExplosive	StickyGrenade	Attaches to surface	2.5s	Yes	Yes	Yes
_explodeOnImpact + _isExplosive	ImpactGrenade	Instant on collision	None	No	Yes	Yes
None	Smoke/Flare	Non-lethal visual	180s	No	No	No

How This Differs from SDG Docs

• SDG docs describe grenade throw force as "configurable per grenade." Community resources suggest per-throwable force values. In the SDK, strongThrowForce, weakThrowForce, and boostForceMultiplier are asset-level fields shared by all throwables. Per-grenade customization requires per-asset values.
• SDG docs claim smoke grenades are non-explosive. The wiki lists smoke as a separate item category. In the SDK, smoke is a throwable with no flags set (no explosive, flash, sticky, or impact). It is handled by a separate Smoke MonoBehaviour but shares the throwable asset base.
• SDG docs reference "fragmentation" as a damage type. Community discussion mentions fragmentation damage vs. blast damage. In the SDK, DamageTool.explode applies uniform radial damage with linear falloff — there is no fragmentation sub-type.

Performance Considerations

Each throwable instantiation creates a GameObject with Rigidbody, Collider, and a behavior component. Object pooling is not used — each throw is a fresh instantiate. With rapid grenade spam (5 throws/second from 10 players), this generates 50 GameObject.Instantiate calls per second. Each explosion performs one Physics.OverlapSphere. This is acceptable on modern hardware but may cause stuttering on lower-end servers during heavy firefights.

Deeper FAQ

Q: Can the fuse timer be cancelled mid-throw?

No. Once the throwable leaves the player's hand (prefab instantiated and force applied), the fuse starts on the server. There is no "catch grenade" or "defuse" mechanic.

Q: What determines flashbang duration per player?

Flash duration is inversely proportional to distance from the flashbang epicenter. A player at the center gets full bright + full deaf; a player at range gets minimal effect. The formula is 1 - (distance / range).

Q: Can throwables damage the thrower?

Yes. DamageTool.explode applies damage to all entities in the blast radius, including the thrower. There is no self-damage reduction or friendly fire exclusion.

Cross-References

• Charge Explosive Asset — ItemChargeAsset — Placed explosives vs. thrown explosives comparison.
• Detonator Asset — ItemDetonatorAsset — Remote detonation vs. timed fuse comparison.
• ItemCaliberAsset — Weapon Mod Base Class — The damage multiplier system inherited by ItemWeaponAsset.
• Interactable Trap — Trigger Damage System — Static trap damage vs. thrown damage comparison.

Document history