Can't Grab, Attempting to release an actor with a null handle

[Findera]

Hi guys,

So, by now I’ve watched the Video several Times, and am pretty sure I did everything as supossed.

The Problem is, When I try grabbing something, nothing happens.
When starting to Play, UE gives me a Warning “Attempting to release an actor with a null handle” but I have no Idea what this is referring to. The PhysicsHandle cant be null with the safety return, right?
Edit: Just saw the log seems to have something to do with the Chaos System

Logging the Name of the HitResult works perfectly fine, so I assume it would be something with the Target Location, but I have absolutely no Idea what could be the Problem.

Google spits out some stuff about actual nullpointers, and something about PhysicsHandle in UE5 being buggy, but I’m way too unexperienced to get something out of that information.

Would be awesome if anyone can help out with this.

Here is my Code for Reference:

Header:

#pragma once

#include "CoreMinimal.h"
#include "Components/SceneComponent.h"
#include "Grabber.generated.h"



UCLASS( ClassGroup=(Custom), meta=(BlueprintSpawnableComponent) )
class CRYPTRAIDER_API UGrabber : public USceneComponent
{
	GENERATED_BODY()

public:	
	// Sets default values for this component's properties
	UGrabber();

protected:
	// Called when the game starts
	virtual void BeginPlay() override;

public:	
	// Called every frame
	virtual void TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction) override;

	UFUNCTION(BlueprintCallable)
	void Release();

	UFUNCTION(BlueprintCallable)
	void Grab();

private:
	UPROPERTY(EditAnywhere)
	float MaxGrabDistance = 400;

	UPROPERTY(EditAnywhere)
	float GrabRadius = 100;

	UPROPERTY(EditAnywhere)
	float HoldDistance = 200;
};

CPP:

#include "Grabber.h"
#include "Engine/World.h"
#include "DrawDebugHelpers.h"
#include "PhysicsEngine/PhysicsHandleComponent.h"

// Sets default values for this component's properties
UGrabber::UGrabber()
{
	// Set this component to be initialized when the game starts, and to be ticked every frame.  You can turn these features
	// off to improve performance if you don't need them.
	PrimaryComponentTick.bCanEverTick = true;

	// ...
}


// Called when the game starts
void UGrabber::BeginPlay()
{
	Super::BeginPlay();	

	UPhysicsHandleComponent* PhysicsHandle = GetOwner()->FindComponentByClass<UPhysicsHandleComponent>();
	if(PhysicsHandle == nullptr){
		return;
	}
}


// Called every frame
void UGrabber::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)
{
	Super::TickComponent(DeltaTime, TickType, ThisTickFunction);

	UPhysicsHandleComponent* PhysicsHandle = GetOwner()->FindComponentByClass<UPhysicsHandleComponent>();
	if(PhysicsHandle == nullptr){
		return;
	}
	FVector TargetLocation = GetComponentLocation() + GetForwardVector() * HoldDistance;
	PhysicsHandle->SetTargetLocationAndRotation(TargetLocation, GetComponentRotation());
}

void UGrabber::Grab()
{	
	UPhysicsHandleComponent* PhysicsHandle = GetOwner()->FindComponentByClass<UPhysicsHandleComponent>();
	if(PhysicsHandle == nullptr){
		return;
	}
	FVector Start = GetComponentLocation();
	FVector End = Start + GetForwardVector() * MaxGrabDistance;
	DrawDebugLine(GetWorld(), Start, End, FColor::Red);

	FCollisionShape Sphere = FCollisionShape::MakeSphere(GrabRadius);
	FHitResult HitResult;
	bool HasHit = GetWorld()->SweepSingleByChannel(HitResult, Start, End, FQuat::Identity, ECC_GameTraceChannel2, Sphere);

	if(HasHit){
		PhysicsHandle->GrabComponentAtLocationWithRotation(HitResult.GetComponent(), NAME_None, HitResult.ImpactPoint, GetComponentRotation());
		UE_LOG(LogTemp, Warning, TEXT("HasHit"));
	}
}

void UGrabber::Release()
{
	UE_LOG(LogTemp, Warning, TEXT("Released Grabber"));
}

[DanM]

So you get this log when you attempt to grab something?

UE_LOG(LogTemp, Warning, TEXT("HasHit"));

[Findera]

Yeah, I can also log Names of the hit actor and the PhysicsHandle at this point without a Problem, it seems to be all there, it just doesn’t grab the thing.
Also, the null handle warning just pops up at the start, not when trying to grab something.

[DanM]

I don’t know why that log happens, I get that as well after upgrading Mike’s project and it still works so you can just ignore it.

Have you tried adding logs in tick to see if SetTargetLocationAndRotation is being called?

[Findera]

Okay, thats good to know.

I tested out logging target location and rotation right after setting them in the tick function, the output changes whenever I move the Camera, so this seems to be working too.

Alright, desperate as i was, after moving the statue around the map up and down, rotating it around and stuff to make sure its not stuck like in the video… i disabled gravity on it and let it hover above the ground and then I could grab it. But only when it moved. The I tried the same with gravity back on, and had the same result.
I can grab it when its moving(falling, or being pushed around by the player pawn or something) but not when it sits around.
That seems really weird to me.

[Findera]

Okay, I don’t know why my Unreal Version seemed to behave differently, but the next Lecture with Waking Rigidbodies seems to fix the issue.
Anyways, thanks for your quick help and input