UE4

#include "Runtime/Engine/Classes/Kismet/KismetMathLibrary.h"

//省略大部分代码
void AMyFPS_Character::OnMoveingOrRot()
{
    GetActorLocation();
    //LineTraceSingle_NEW();
    if (GEngine != nullptr)
    {
        FHitResult hit;
        auto temp_startPos = GetActorLocation();
        auto temp_rota = GetActorRotation();

        auto temp_endPos = FRotationMatrix(temp_rota).GetScaledAxis(EAxis::X) * 500.0f; // + 
        //hit.
        m_bodyInstance.LineTrace(hit, temp_startPos, temp_endPos, false, false);
        if (hit.Actor != nullptr && hit.Actor != this)
        {
            m_operaTarget = hit.Actor;
        }
    }
}

//Exa 2

//In player controller class
 
//location the PC is focused on
const FVector Start = GetFocalLocation(); 
 
//256 units in facing direction of PC (256 units in front of the camera)
const FVector End = Start + GetControlRotation().Vector() * 256; 
 
//The trace data is stored here
FHitResult HitData(ForceInit);
 
//If Trace Hits anything
if(  UMyStaticFunctionLibrary::Trace(GetWorld(),GetPawn(),Start,End,HitData)  )
{
	//Print out the name of the traced actor
	if(HitData.GetActor())
	{
		ClientMessage(HitData.GetActor()->GetName());
 
	        //Print out distance from start of trace to impact point
	        ClientMessage("Trace Distance: " + FString::SanitizeFloat(HitData.Distance));
	}
}