Unreal Eye Tracking Offset

[C3D]

I'm doing some testing with Unreal 4.25 and SRanipal 1.3.0.9. I've calibrated the Eye Tracker, imported the SDK, opened the EyeSample level and gazed at the dartboard sample objects. All works great.

However, when I move away from the level origin (ie 0,0,0), even just a few steps from my desk, I noticed the eye tracking on the dartboards to be very offset, to the point that the gaze is unusable. This is corrected when I step back toward the level origin.

Is this just an issue with the dartboard examples? I don't recall this issue from previous versions of SRanipal, but I don't have the old installers to test. Anyone else noticing this behaviour?

Thanks @MariosBikos_HTC

[C3D]

Just wanted to check in with this. I still don't know if this is intended behaviour. Here's the repro steps:

1. Install the SDK (1.3.0.9) in Unreal Engine 4.25.4
2. Open the EyeSample level
3. Walk around a bit and look at things
4. Notice that the gaze is appears incorrect when you walk away from the origin

Is this the intended behaviour? I would like to know if I should support this or if I'll have to redo some work when the next version drops.

Thanks

[MariosBikos]

Hi @C3D,

I managed to reproduce the issue and have already sent a request for the team to have a look. It looks like the Focus function is not behaving properly but the GetGazeData returns the proper output. Can you check if the GetGazeData works for you until we fix the issue?

[C3D]

Hi Marios,

GetGazeData seems to work and that will likely be my preferred method. This GazeData is in local space and needs to be offset and rotated by the PlayerCameraManager's transform to get the Origin and Direction in world space. Is that correct? It seems Focus returns the world space of the hit result, so doing some testing on these dartboards isn't a 1-to-1 change, but not too tricky.

Nice to hear it's just something with the Focus function and not lower level. I can work with that.

Thanks

 

[MariosBikos]

Hi @C3D,

there was an issue indeed in our SDK and the team managed to fix it. This will be updated in SRanipal v1.3.1.1 but here is an image showing the required code change if you want to fix it earlier than that. Please use this and let us know if it worked.

 

[C3D]

Hey Marios,

Sorry for the delayed response. Good to hear the fix is incoming!

I would test out that change, but the image isn't loading for me. It looks like this:

 

[Tomas_TDFM]

Hi @MariosBikos_HTC,

when we could expect the SRanipal update? Is it coming in days/weeks? I´m working on eye tracking presentation and update would be appreciated.

Thanks.

[MariosBikos]

Hi @Tomas_TDFM, version 1.3.1.1 should include the fix I mentioned in this thread. I am double-checking that but it looks like the next version should be ready & public early next week. Until then you can always manually change the code if you have a C++ project.

[Tomas_TDFM]

@MariosBikos_HTC Thank you for the information. And could you send that code again please? We can´t see the image you posted, as C3D mentioned. It would be great and I have no problem changing the code. Thanks.

[MariosBikos]

Ah sorry about that @Tomas_TDFM, @C3D let me re-upload the image here. Let me know if it's visible.

What you need to do is go to SRanipal\Source\SRanipalEye\Private\SRanipalEye_Core.cpp file and replace line 337: 

RayCastDirection = PlayerMainCameraRotation.RotateVector(PlayerMainCameraLocation + CameraGazeDirection * maxDistance);

with the following:

RaycastDirection = (PlayerMainCameraRotation.RotateVector(CameraGazeDirection)*maxDistance) + PlayerMainCameraLocation;