Vive Tracker - Can be tracked in editor?

Development Platform & Builds XR Development
1

Hello there,
I know it is possibile to have the Vive Tracker to be tracked in editor, without Play or Simulate, but I can’t figure out how to achieve this.
I use Unreal for Virtual Production purpose and I need the Vive Tracker to drive a VCam, possibily without hitting Play.
Thx

2

Good question…for body mocap I use IKinema Orion, which is a standalone software that gets the Vive Trackers position and send it to UE4, and it does work without being in either Play/Simulate.
I think that you can do the same thing, but using the data coming from SteamVR, but honestly I haven’t found any usefull informations as well.

May I ask why you need it to work without being in Play/Simulate?
Because having a Vive Tracker onto a camera is very easy to integrate and use in Virtual Production.

3

I was really curious so I tested it. Yes, it’s possible, but with a bit of C++ (only to make it Tick in editor, not to get coordinates of vive tracker).

This isn’t 100% working code, you need to use multiple static mesh components and bind them to device IDs, but I hope it gives an idea.

Header:


#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "ViewportTicker.generated.h"

UCLASS()
class VIVEMOCAP_API AViewportTicker : public AActor
{
    GENERATED_BODY()

public:    
    AViewportTicker();
    virtual void Tick(float DeltaTime) override;

    UPROPERTY(VisibleDefaultsOnly, BlueprintReadOnly, Category = "Components")
    class UStaticMeshComponent* TrackerMesh;

    virtual bool ShouldTickIfViewportsOnly() const override
    {
        return true;
    }
};

Source:


#include "ViewportTicker.h"
#include "Components/StaticMeshComponent.h"
#include "SteamVRFunctionLibrary.h"

AViewportTicker::AViewportTicker()
{
    PrimaryActorTick.bCanEverTick = true;
    PrimaryActorTick.bStartWithTickEnabled = true;

    RootComponent = CreateDefaultSubobject<USceneComponent>(TEXT("RootComponent"));

    TrackerMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("TrackerMesh"));
    TrackerMesh->SetupAttachment(RootComponent);

}

void AViewportTicker::Tick(float DeltaTime)
{
    Super::Tick(DeltaTime);

    TArray<int32> DeviceIds;
    TArray<int32> TrackerIds;
    USteamVRFunctionLibrary::GetValidTrackedDeviceIds(ESteamVRTrackedDeviceType::Controller, DeviceIds);
    USteamVRFunctionLibrary::GetValidTrackedDeviceIds(ESteamVRTrackedDeviceType::Other, TrackerIds);
    DeviceIds.Append(TrackerIds);

    if (DeviceIds.Num() > 0)
    {
        FVector loc;
        FRotator rot;
        USteamVRFunctionLibrary::GetTrackedDevicePositionAndOrientation(DeviceIds[0], loc, rot);
        TrackerMesh->SetRelativeLocationAndRotation(loc, rot);
    }
}
4

I am building a muticamera setup, that streams to a video mixer via Blackmagic. I use the new features of Composure, and is very handy to have all functioning in editor, for production reasons.

5

Thank you, i’ll check this. I am not a programmer, so I don’t think i’ll understand everything. Also a cinecamera must be parented to the tracker, so I think i’ll need coordinates to make this useful.
Any chance this thing can be done or explored using blueprints? I understand a little coding, but it is beyond my skills to really use it in production.

6

@FabioA
You can get tracker’s coordinates in blueprint using the same two functions: GetValidTrackedDeviceIds and GetTrackedDevicePositionAndOrientation. But Tick event doesn’t work in viewport without simulation mode unless ShouldTickIfViewportsOnly function returns true. And you can only override ShouldTickIfViewportsOnly function in c++.

Probably you can use Python instead to extend editor’s functionaliy - but i’m not sure.

7

So, I added this functionality to my helper mini-plugin. You can download it here, then copy to [your project]/Plugins folder or [engine version]/Engine/Plugins/Marketplace.
In your project, create blueprint inherited from “Editor SteamVR Controller” and place it on level, then in Details panel add any objects to “Tracked Objects” map. Good luck!

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8

Thank you very much! I’ll try today and i’ll let you know.

Thank you again!​​​​​​​

9

If you needed lastest version:

  • open my ViveMocapKit page on Marketplace (link in my signature)
  • download “Demo Project (for motion capture)” (it won’t work without ViveMocapKit plugin, but you don’t need it)
  • extract and copy ViveMocap/Plugins/SteamVRTrackingLib to you project’s “Plugins” folder.