Question on UCharacterMovementComponent->ApplyRootMotionSource and replication | Unreal Source | Page 1

hearty ice Jul 26, 2025, 12:09 AM

    if (UCharacterMovementComponent* MovementComponent = Cast<UCharacterMovementComponent>(GetMovementComponent()); MovementComponent !=
        nullptr)
    {
        MovementComponent->RemoveRootMotionSourceByID(RootMotionSourceID);

        TSharedRef<FRootMotionSource_MoveToForce> RootMotionSource = MakeShared<FRootMotionSource_MoveToForce>();
        RootMotionSource->InstanceName = FName("RootMotionMoveToForce");
        RootMotionSource->AccumulateMode = ERootMotionAccumulateMode::Override;
        RootMotionSource->Settings.SetFlag(ERootMotionSourceSettingsFlags::UseSensitiveLiftoffCheck);
        RootMotionSource->Priority = 1000;
        RootMotionSource->StartLocation = MoveStartLocation;
        RootMotionSource->TargetLocation = MoveEndLocation;
        RootMotionSource->Duration = 1;
        RootMotionSource->bRestrictSpeedToExpected = false;
        RootMotionSource->FinishVelocityParams.Mode = ERootMotionFinishVelocityMode::SetVelocity;
        RootMotionSource->FinishVelocityParams.SetVelocity = FVector::ZeroVector;

        RootMotionSourceID = MovementComponent->ApplyRootMotionSource(RootMotionSource);
        UE_LOG(LogTemp, Display, TEXT("Do move local role %s, is locally owned? %hhd"), *UEnum::GetValueAsString(GetLocalRole()), IsLocallyControlled())
    }

Here's where I'm applying the root motion source, possibly there's some config I'm missing, or some function I'm not calling?

Question on UCharacterMovementComponent->ApplyRootMotionSource and replication

Here's what it looks like, in the video I move in and out of cover (press and release space bar) twice on the server, and then twice on the client.

hearty ice Jul 26, 2025, 12:45 AM

In this version, I send a server RPC from the client to apply the same root motion source, but you can see that there's a lot of corrections being made, resulting in the jitter.

LogNetPlayerMovement: Warning: *** Client: Error for BP_TimeShooterCharacter_C_0 at Time=21.117 is 0.000 LocDiff(X=0.000 Y=0.000 Z=0.000) ClientLoc(X=450.000 Y=50.040 Z=298.400) ServerLoc(X=450.000 Y=50.040 Z=298.400) NewBase: Lvl_Test:PersistentLevel.StaticMeshActor_34.StaticMeshComponent0 NewBone: None ClientVel(X=0.000 Y=0.000 Z=0.000) ServerVel(X=0.000 Y=0.000 Z=0.000) SavedMoves 12

#Question on UCharacterMovementComponent->ApplyRootMotionSource and replication