Troubleshooting

This section discusses common problems when using the Unreal Engine Plugin. If the Unreal Engine Plugin does not work properly, refer to the following information to troubleshoot.

Common problems

1. Cannot see the mocopi live link folder in the content browser
2. Cannot see Unreal mannequin in my scene after placing
3. Actor does not move (motion data cannot be received)
4. Motion data is not received using UDP (No source subject name listed)
5. Motion data is not received (yellow dot for the source or no source instance listed)
6. mocopi mannequin does not move, but motion data is being received (green dot for the source)
7. Unreal mannequin does not move, but motion data is being received (green dot for the source)
8. Unreal metahuman does not move, but motion data is being received (green dot for the source)
9. Actor has moved/drifted significantly from where I placed it
10. Actor's transform and rotation data are being tracked, but no other animation data is being received
11. Take Recorder recordings are coming out as empty data
12. Cannot create a mocopi source; I get an error about a missing library
13. Compilation and Packaging: cannot compile the UE plugin on Mac, arithmetic compilation error
14. Packaging: on Mac, packaging the mocopi plugin succeeds, but the game does not run
15. Packaging fails and I get an error about missing Metahuman and/or UE Mannequin assets
16. Packaging: Packaging fails, "An item with the same key has already been added, Key: MocopiLiveLink

Cannot see the mocopi live link folder in the content browser

1. On the content browser, navigate to the top right where it says "Settings" and ensure that "Show Plugin Content" is selected.

Cannot see Unreal mannequin in my scene after placing

1. Make sure that you have the required assets for the Unreal mannequin as the plugin assumes that you have them. The plugin uses the UE mannequin asset (Manny) that come in the "Third Person Game Project" template.

Actor does not move (motion data cannot be received)

When no data is coming in, the source subject name is not listed yet. Check the following:

1. Check that the development environment meets the requirements.
2. If using WiFi to connect, check that phone has wifi enabled and you are connected to the same access point as the PC.
3. Confirm that the mocopi app is in "Motion" > "Send" mode and not in "Motion" > "Save" mode and that "Streaming" started.
4. Check that the IP address of the mocopi app connection destination is the IP address of the PC which is running Unreal Engine.
5. Check that the port number for sending and receiving UDP matches.
6. Check that the mocopi app transmission format is set to "mocopi (UDP)."
7. If there are no problems with the settings above, refer to Motion data is not received using UDP next.

Motion data is not received using UDP (No source subject name listed)

UDP transmissions may be blocked at the firewall. Check the firewall settings of the development environment OS and make sure that communication is permitted at the port number that receives UDP transmission from the mocopi app. If the communication is blocked, set it to be permitted.
Also if using WiFi, check your router settings to ensure the UDP protocol and ports are allowed.

The following is a Windows Firewall configuration example.

1. Open the "Windows Firewall with Advanced Security" in Windows.
2. Click [Inbound Rules] to display the list.
3. Right-click "Unreal Editor" and open the Properties.
4. Add a check mark to the network which corresponds to the development environment under "Profiles" in the [Advanced] tab.
5. Ensure that the "Protocol type" field in the "Protocols and Ports" tab is set to "Any" or "UDP."

Motion data is not received (yellow dot for the source or no source instance listed)

In this scenario, there was data coming in for a moment and then the streaming was interrupted for some reason.

1. Check that the development environment meets the requirements.
2. Confirm that data streaming was not stopped on the mocopi mobile app
3. If using WiFi, verify the phone did not switch to a different Wifi network
4. If using wired network adapter on the phone, check that there is no loose cable or adapter
5. Check that the mocopi app transmission format is set to "mocopi (UDP)."
6. Check that the Unreal computer is NOT connected to multiple networks (Wifi and wired) and that the IP you are obtaining is on the same network as your phone

mocopi mannequin does not move, but the motion data is being received (green dot for the source)

In this scenario, the plugin is communicating with the mocopi app and receiving motion data, but the motion is not reflected in the actor.

1. Check that the mocopi source that drives your character is still present, (was not deleted), and that it is enabled (checkbox selected)
2. Check that the mocopi source name (LiveLink source) selected in the ABP_mocopi file matches the Subject Name of the mocopi source in your project
3. If multiple characters share the same custom name, make sure that the correct character name has the checkbox enabled (only 1 out of multiple characters sharing the same name can be enabled at any given time)

Unreal mannequin does not move, but the motion data is being received (green dot for the source)

In this scenario, the plugin is communicating with the mocopi app and receiving motion data, but the motion is not reflected in the actor.

1. First, refer to mocopi mannequin does not move, but the motion data is being received (green dot for the source).
2. Check in the MannequinActor file, in the "Source_SkeletalMesh" Details, that the Animation Class is "ABP_Mocopi" and the "Skeletal Mesh is "MocopiMannequin" (as described in the user guide) . You can re-select the files as a way to ensure that the proper file linkage exists
3. Check in the MannequinActor file, in the "Target_SketletalMesh" Details, that the Animation class is "ABP_Mannequin" and the "Skeletal Mesh Asset" is "SKM_Manny" or a UE5.x-compatible Unreal Mannequin (as described in the user guide). You can re-select the files to ensure the correct files linkage
4. If multiple characters share the same custom name, make sure that the correct character name has the checkbox enabled (only 1 out of multiple characters sharing the same name can be enabled at any given time)

Unreal metahuman does not move, but the motion data is being received (green dot for the source)

In this scenario, the plugin is communicating with the mocopi app and receiving motion data, but the motion is not reflected in the actor.

1. First, refer to mocopi mannequin does not move, but the motion data is being received (green dot for the source).
2. Make sure that all plugins that need to be enabled for the metahuman to animate, as well as all the required settings are enabled in your project
3. Check the Blueprint (BP) file of the metahuman you are trying to animate and confirm for the "Source_SKM", that the mocopi references are correct, as described in the user guide. You can re-select the files if you prefer, to ensure correct files linkage
4. Check the Blueprint (BP) file of the metahuman you are trying to animate and confirm that the "Body" Skeletal Mesh Details, shows the correct Anim Class as described in the user guide.
5. If multiple characters share the same custom name, make sure that the correct character name has the checkbox enabled (only 1 out of multiple characters sharing the same name can be enabled at any given time)

Actor has moved/drifted significantly from where I placed it

1. To ensure the best quality animation, we encourage periodically recalibrating, including immediately prior to any recordings.
2. Performing a reset position will reset the actor to the location it was placed and will correct any gradual drift that might accumulate throughout a recording session.

Actor's transform and rotation data are being tracked, but no other animation data is being received

This stems from Unreal getting confused as to where to put the motion data. A common solution for this is to:

1. Check that under the Live Link settings of your actor, under "Live Link Body Subj" that "MocopiSkeleton" is selected.
2. Ensure that "Use Live Link Body" is NOT selected
3. Under Live Retarget settings of your actor check that "use Live Retarget Mode" is NOT selected.

Take Recorder recordings are coming out as empty data

If you are having the error that the recording itself is empty of all values and keyframes, please make sure to have the "Use Source Timecode" setting enabled in your source and to be using the latest mocopi mobile app when sending the motion data.

Cannot create a mocopi source; I get an error about a missing library

If you get an error when trying to create a new mocopi source.

1. Re-install the plugin to ensure that you have all the plugin files in place.

Compilation and Packaging: cannot compile the UE plugin on Mac, arithmetic compilation error

If you are on Mac environment trying to compile the plugin, and you are seeing a compilation error indicating Arithmetic between different enumeration types, you can add the below code snippet to to the ”Target.cs” file of your C++ project, inside the Target definition, to resolve the issue:

Packaging: on Mac, packaging the mocopi plugin succeeds, but the game does not run

This may occur when you are packaging a BP project on Mac (on the most recent version of UE 5.1 and UE 5.0) and your plugin is installed to your Project. For packaging to work, you will need to package into a C++ game. If you have a BP project, you can convert it to a C++ game, by adding an empty class to your project. Then you will need to add the "compiler flag" mentioned on this page, to prevent an "arithmetic compilation error".

Packaging fails and I get an error about missing Metahuman and/or UE Mannequin assets

If you don't have any Metahuman or Unreal Mannequin assets in your project, you will need to remove the files listed below for successful packaging:

• Plugins/MocopiLiveLink/Content/Metahuman/ABP_Metahuman
• Plugins/MocopiLiveLink/Content/UnrealMannequin/ABP_Mannequin

Packaging: Packaging fails, "An item with the same key has already been added, Key: MocopiLiveLink

This issue may be seen on the latest versions of Unreal Engine, if you have the plugin installed to both your project and the Engine and you are trying to package a Blueprint project.
We only support packaging C++ projects, you will need to convert your BP project to C++ project. Then you may need to add the compiler flag referenced on this page, to prevent an "arithmetic compiler error" on UE 5.0 and UE 5.1 on Mac.