GAS Quick Reference

A condensed reference for the Gameplay Ability System concepts used by Motion. For in-depth explanations, see the full GAS Primer.

The 5 Core Concepts

Concept	What It Is	Motion's Use
ASC	AbilitySystemComponent - manages everything	Lives on PlayerState, discovered via IAbilitySystemInterface
Attributes	Numeric values (speed, stamina)	WalkSpeed, Stamina, MaxStamina, JumpVelocity
Effects	Change attributes & grant tags	Sprint speed boost, stamina drain/regen
Tags	Hierarchical state labels	Motion.State.Sprinting, Motion.State.Crouching
Abilities	Actions triggered by input	Motion uses components, not traditional abilities

Quick Setup Checklist

1. PlayerState implements IAbilitySystemInterface
2. PlayerState owns AbilitySystemComponent
3. PlayerState owns AttributeSet (or Motion discovers attributes by name)
4. GameMode uses your PlayerState class
5. Motion components auto-discover ASC

Motion's Gameplay Tags

State Tags

Tag	Component	Purpose
Motion.State.WantsToSprint	Sprint	Input intent
Motion.State.Sprinting	Sprint	Active sprinting
Motion.State.WantsToCrouch	Crouch	Input intent
Motion.State.Crouching	Crouch	Active crouching
Motion.State.WantsToJump	Jump	Input intent
Motion.State.Jumping	Jump	In air from jump
Motion.State.StaminaDepleted	Sprint	Exhausted
Motion.State.StaminaRegenBlocked	Sprint	Regen on cooldown
Motion.State.Walking	Walk	Has velocity > 0
Motion.State.MovementHalted	-	Movement completely halted
Motion.State.StaminaRegenerating	Sprint	Actively regenerating

Ability Tags

Tag	Purpose
Motion.Ability.CanJump	Character can perform jump actions
Motion.Ability.CanCrouch	Character can perform crouch actions
Motion.Ability.CanSprint	Character can perform sprint actions

Camera Tags

Tag	Purpose
Motion.Camera.BreathingActive	Camera breathing effect is active
Motion.Camera.DisableShake	Camera shake effects temporarily disabled

Attribute Tags

Tag	Attribute
Attribute.Movement.WalkSpeed	Walk speed
Attribute.Movement.SprintSpeed	Sprint speed modifier
Attribute.Movement.JumpVelocity	Jump velocity
Attribute.Stamina.Current	Current stamina
Attribute.Stamina.Max	Maximum stamina
Attribute.Stamina.RegenRate	Stamina regen rate

SetByCaller Magnitude Tags (Advanced)

Tag	Purpose
SetByCaller.Magnitude.WalkSpeed	Walk speed modification
SetByCaller.Magnitude.CrouchSpeed	Crouch speed modification
SetByCaller.Magnitude.SprintSpeed	Sprint speed modification
SetByCaller.Magnitude.JumpVelocity	Jump velocity modification
SetByCaller.Magnitude.StaminaCost	Stamina cost amount
SetByCaller.Magnitude.StaminaDrain	Stamina drain rate
SetByCaller.Magnitude.StaminaRegen	Stamina regen rate

Motion's Gameplay Effects

Movement Effects

Effect	Type	Purpose
GE_Motion_SprintSpeed	Infinite	+300 walk speed
GE_Motion_CrouchSpeed	Infinite	-200 walk speed

Stamina Effects

Effect	Type	Purpose
GE_Motion_SprintStaminaDrain	Infinite	Drain while sprinting
GE_Motion_SprintStaminaRegen	Infinite	Regenerate when not sprinting
GE_Motion_SprintStaminaRegenDelay	Duration	Block regen after exhaustion

Tag Effects

Effect	Grants Tag
GE_Motion_WantsToSprint	Motion.State.WantsToSprint
GE_Motion_Sprinting	Motion.State.Sprinting
GE_Motion_WantsToCrouch	Motion.State.WantsToCrouch
GE_Motion_Crouching	Motion.State.Crouching
GE_Motion_WantsToJump	Motion.State.WantsToJump
GE_Motion_Jumping	Motion.State.Jumping

Motion's Attributes

Attribute	Default	Description
WalkSpeed	600	Base walking speed
Stamina	5.0	Current stamina
MaxStamina	5.0	Maximum stamina
StaminaDrainRate	1.0	Drain per second
StaminaRegenRate	1.0	Regen per second
JumpVelocity	420	Base jump velocity

Effect Duration Types

Type	Behavior	Example
Instant	Permanent change	Damage
Duration	Temporary with timer	10s speed buff
Infinite	Until manually removed	Sprint speed while sprinting

Common Patterns

Checking Tags (Blueprint)

Has Gameplay Tag (Actor, Tag) -> Boolean

Checking Tags (C++)

UMotionAbilitySystemHelper::ActorHasGameplayTag(Actor, Tag)

Applying Effects (Server Only)

FGameplayEffectContextHandle Context = ASC->MakeEffectContext();
FGameplayEffectSpecHandle Spec = ASC->MakeOutgoingSpec(EffectClass, 1.0f, Context);
ASC->ApplyGameplayEffectSpecToSelf(*Spec.Data.Get());

Removing Effects

ASC->RemoveActiveGameplayEffect(EffectHandle);

Debugging Commands

# View GAS state
showdebug abilitysystem

# Log GAS activity
log LogAbilitySystem Verbose
log LogGameplayTags Verbose
log LogMotionAbilitySystem Verbose

Common Issues

Problem	Likely Cause	Solution
Tags not replicating	Using loose tags instead of effects	Use GameplayEffect to grant tags
Attributes not syncing	Effect not applied on server	Apply effects only with HasAuthority()
ASC not found	PlayerState missing interface	Implement IAbilitySystemInterface
Effect not applying	Missing AttributeSet	Add AttributeSet to ASC

See Also

• Full GAS Primer - Complete explanations
• Architecture - How Motion integrates with GAS
• Networking - GAS replication in Motion