Azure Kinect Unreal Plugin

This Unreal (4.25) project contains the Azure Kinect Plugin and sample map to test the Plugin. The Plugin integrates the Azure Kinect Sensor SDK (K4A) and Azure Kinect Body Tracking SDK (K4ABT). It captures and processes the Body Tracking data and maps it onto the Unreal Mannequin skeletal mesh. The plugin supports tracking up to a maximum of 10 bodies.

SDKs

• Azure Kinect SDK 1.4.1
• Azure Kinect Body Tracking SDK 1.0.1

To get up and running

1. Add the <Azure Kinect Body Tracking SDK installation>/tools folder to the Path variable in Environment Variables for User or System.
2. If you want to enable Azure Kinect logging, run the following 4 commands in Command Prompt as an admin:
   setx K4A_ENABLE_LOG_TO_A_FILE k4a.log /M
setx K4A_LOG_LEVEL w /M
setx K4ABT_ENABLE_LOG_TO_A_FILE k4abt.log /M
setx K4ABT_LOG_LEVEL w /M
   The logs will be found in the path <unreal_installation_folder>/Engine/Binaries/Win64/ in the files k4a.log for Azure Kinect and k4abt.log for Azure Kinect Body Tracking.

The Notes section below has more FYI.

Plugin Files

• AzureKinectManager : A singleton class used in Blueprints to control and get info from the connected Azure Kinect Device(s).
• AzureKinectDevice : A representation of the Native Azure Kinect Device that is used to call the connected device's (K4A & K4ABT) API for starting & stopping camera sensors, creating & destroying the body tracker, capturing the body frame etc.
• AzureKinectThread : A thread that is used to capture the Azure Kinect device's body frame data.
• AzureKinectBody : A representation of the Native Azure Kinect Body that contains Joints.
  • AzureKinectJoint : A representation of the Native Azure Kinect Body Skeleton joint. This stores the kinect skeleton joint position and orientation data by converting them from Kinect camera co-ordinate system to Unreal co-ordinate system and maps them to the Unreal mannequin.
• AzureKinectHelper : A helper file that contains the duplicated Azure Kinect enums for Blueprint access and constant values for maximum bodies tracked and the joints count.

Sample Files for Testing

Blueprints/

• BP_AnimMannequin : The animation blueprint that applies the Orientation of the joints from the plugin to the UE4 mannequin.
• BP_MannequinActor : A test blueprint actor with 1 UE4 mannequin skeletal mesh that uses the above animation blueprint.
• BP_TenMannequinActors : A test blueprint actor with 10 UE4 mannequin skeletal meshes that use the above animation blueprint.
• BP_TestActor : A test blueprint actor with 26 spheres where each one represents a joint in Azure kinect body skeleton.The spheres use the Position data from the plugin for their corresponding joints that they each represent.

Maps/

• Sample : This map contains the BP_TestActor and BP_MannequinActor already placed in the level for testing.

Notes

The Azure Kinect project will need to reference the following dll to function:

k4a.dll  
k4abt.dll  
depthengine_2_0.dll  
dnn_model_2_0.onnx  
onnxruntime.dll  
cudnn64_7.dll  
cudart64_100.dll  
cublas64_100.dll  

We've included some of these dlls in Project/Plugins/AzureKinectUnreal/Binaries/Win64, just to allow the project to compile when opened directly after cloning:

k4a.dll
k4abt.dll
depthengine_2_0.dll
dnn_model_2_0.onnx
onnxruntime.dll  

If you're getting errors with dlls or libraries not loading properly, check if the libraries that exist in these places are all of the same version.
Kindly note that the dlls/libraries should only be in one of the below locations.

• <Azure Kinect Body Tracking SDK installation>/tools, if this has been added to your PATH in the environmental variables. This is the best place to keep them, as it's the location all Azure Kinect stuff uses. You can have the libraries exist only here and nowhere else, and it should work just fine. (or)
• <Unreal Installation Folder>/Engine/Binaries/Win64/. You don't have to put any dlls or libraries here if you have the body tracking sdk tools in your PATH. (or)
• Plugins/AzureKinectUnreal/Binaries/Win64/. We've included some dlls here to make sure it compiles from a straight clone. You can delete them if they mismatch with your body tracking SDK version and it's added to your PATH.

Disclaimer

• The plugin supports tracking with one connected Azure Kinect device for tracking one body.

• The plugin has not been thoroughly tested with one connected Azure Kinect device for tracking multiple bodies although the plugin supports it.

• The plugin has not at all been tested with multiple Azure Kinect Devices connected to one PC.

Troubleshooting

Kindly check the logs (Project, k4a.log, k4abt.log) to see if there is anything regarding the issue you are having trouble with and raise a Github Issue with the information found in logs.

The Project doesn't open.

Delete the Project/Binaries and only the UE4 dlls in the Plugin/AzureKinectUnreal/Binaries folder and try again. If it still doesn't open, try building the Project in Visual Studio and check if there are any issues.

Kindly check the project log file to see what the issue is. It is located in <project>/Saved/Logs/ folder.

Also, check if Plugin/AzureKinectUnreal/Binaries contains the dependent dll files k4a.dll, k4abt.dll and depthengine_2_0.dll.

Unreal crashes when PIE (Play in Editor).

Kindly check the following.

• Path Environment variable has the <Azure Kinect Body Tracking SDK installation>/tools folder added.
• The Plugins/AzureKinectUnreal/Binaries/Win64 contains the k4a.dll, k4abt.dll, depthengine_2_0.dll and dnn_model_2_0.onnx files.
• The version of Azure Kinect Sensor SDK and Azure Kinect Body Tracking SDK installed in your PC is the same as mentioned above under SDKs section.

Pressing play doesn't show anything.

Kindly check the Output Log window and if the issue is something related to the Device then check the k4a.log and if it is related to the Body Tracking then check the k4abt.log. These log files can be found in <unreal_installation_folder>/Engine/Binaries/Win64/.

If these log files are not present then kindly check here in order to enable the logs.

The project can't find the Azure Kinect

Kindly check if the Azure Kinect shows up under the Cameras section of the Device Manager. It sometimes doesn't connect on startup, which can be fixed by unplugging the USB core and plugging it back in. The white LED on the front will show it connecting.