DllNotFoundException (Error) when using SRanipal and Eye Tracking SDK

[Justine]

Hi @chengnay,

Please see below:

Alienware Aurora Ryzen Edition:

Device name    DESKTOP-CSTO532
Processor    AMD Ryzen 9 5900 12-Core Processor                3.00 GHz
Installed RAM    64.0 GB
System type    64-bit operating system, x64-based processor
Pen and touch    No pen or touch input is available for this display
 

Please let me know if you require any further information. Thanks.

[Govert]

I'm running into the same error.

FYI: it works for me in the 2019 editor, in 2020 and 2021 it fails

[Justine]

Hi @chengnay,

 

So, I reached out to someone with Unity experience to visit my office and check the issue, and she managed to resolve the DLL error. She mentioned that the issue might be from a bug in the XR plugin when using OpenXR. So instead, I installed the SteamVR Plugin to my project. If you have any suggestions on how to enable OpenVR (without using the SteamVR plugin) instead of OpenXR, please let me know.

Please find the below summary of our troubleshooting session:

Problem:

Compatibility issue between OpenXR (Unity) and SRanipal SDK that causes the error "DllNotFoundException : Assets/ViveSR/Plugins/SRanipal.dll '' to appear.

Solution:

Uninstall XR from Unity and install SteamVR to use OpenVR instead of OpenXR.

But at this stage of your project the above steps caused issues and errors.

As a second plan I did the following:

1- Created a new Project that uses URP.

2- Installed SteamVR to this project.

3- Imported SRanipal SDK to this project.

4- Exported your project as a package and unchecked all the XR and the SRanipal SDK related folders.

5- Imported the previous package to the new project.

6- Because you were using a player that's provided from XR Interactions, I had to delete it too and replace it with "Player" prefab from SteamVR which has many more functionalities. For example : hand movements.

7- Tested it and made sure everything was working as intended.

 

[VIVE_chengnay]

Hi @Justine,

It is glad to hear that your issue is resolved.

Thanks for sharing the information.

Unfortunately, there is no other method to enable OpenVR without using SteamVR Unity Plugin.

May I know why you don't want to use SteamVR Unity Plugin?

[VIVE_chengnay]

Hi @Govert,

2 hours ago, Justine said:

Problem:

Compatibility issue between OpenXR (Unity) and SRanipal SDK that causes the error "DllNotFoundException : Assets/ViveSR/Plugins/SRanipal.dll '' to appear.

Solution:

Uninstall XR from Unity and install SteamVR to use OpenVR instead of OpenXR.

But at this stage of your project the above steps caused issues and errors.

As a second plan I did the following:

1- Created a new Project that uses URP.

2- Installed SteamVR to this project.

3- Imported SRanipal SDK to this project.

4- Exported your project as a package and unchecked all the XR and the SRanipal SDK related folders.

5- Imported the previous package to the new project.

6- Because you were using a player that's provided from XR Interactions, I had to delete it too and replace it with "Player" prefab from SteamVR which has many more functionalities. For example : hand movements.

7- Tested it and made sure everything was working as intended.

Could you check in 2020 and 2021, is OpenXR selected too?

[Justine]

Hi @chengnay,

No specific reason, just out of curiosity.

Also, now that the Eye Tracking SDK works with me, I would like to know how to extract Eye Data in my project. I saw a sample script in one of the Vive Forums on how to extract Eye Data, however, it is not working for me. Can you please advise me on how I can extract eye data?

Please find link to the forum: 

 

[VIVE_chengnay]

Hi @Justine,

Do you mean you try the EyeTracker.cs and it couldn't work?

I suggest add some debug logs to find out the root cause why you cannot extract eye data using that script.

I look through the script and it looks ok to me.

[Kate.kate]

Hi! I almost have the same problem but no error warning just unity crashes down as soon as I press play. Did you by chance found a solution?

[Youngwoo]

@Kate.kate 

I'd also reached that issue, and by installing VIVE WAVE OpenXR and turn on the facial tracking feature, I could maintain the project played.

However, then I faced Dll issue, and I'm also trying to resolve it.

 

[VSP MobiLab]

I had the same issues. Either Unity was crashing or the DLL was not found. 

 

Here is my solution:
Tested with Unity 2022.2.3f1 / Unity 2020.3.44f1, VIVE OpenXR Plugin - Windows 1.0.10, SRanipal Runtime 1.3.5.5 and SRanipal SDK 1.3.3.0

• The current SRanipal Runtime (1.3.5.5) should already be installed on your PC after completing the PC VR HEADSET SETUP https://www.vive.com/us/setup/pc-vr/
  • Someone in another thread said you need version 1.3.2.0 to extract eye tracking data. This is not true for me, but you can find the older version here: https://hub.vive.com/en-US/download/
• The current SRanipal SDK (1.3.6.8) makes Unity crash. Get version 1.3.3.0 from the archive: https://developer.vive.com/resources/vive-sense/eye-and-facial-tracking-sdk/download/archive/1_3_3_0/
• If not done yet, install the XR Plugin Management via Edit > Project Settings > XR Plugin Management.
• Add the Vive Package Repository for the Package Manager: Edit > Project Settings > Package Manager > Scoped Registries
  • Name: VIVE
  • URL: https://npm-registry.vive.com
  • Scope(s): com.htc.upm
• Open Package Manager, select My Registries in top row and install VIVE OpenXR Plugin - Windows.
• A pop-up appears and requests the restart of the editor to enable the new input system. Click Yes and wait for the restart to be completed.
• Open XR Plugin Management via Edit > Project Settings > XR Plugin Management.
  • Activate OpenXR and Vive OpenXR feature group.
• Import SRanipal SDK: Assets > Import Package > Custom Package...
• Open OpenXR settings via Edit > Project Settings > XR Plugin Management > OpenXR
  • Unselect Facial Tracking, Hand Tracking and Scene Understanding.
• Close and re-open Unity! Without the restart, the DLL won't be found. (Took me hours to figure this out.)
• Test if everything works by dragging the SRanipal Eye Framework prefab in your Scene and running the scene.

I followed this tutorial for extracting the eye data and adapted the script to my needs, works perfectly: https://forum.htc.com/topic/9341-vive-eye-tracking-at-120hz/