Frequently Asked Questions

I’ve added the plugin to the plugins folder of my project and it says ‘[ProjectName] cannot be compiled’. What do I do?

This is a quirk of Unreal projects that don’t have any C++ code in them (blueprint only projects). To rebuild the Ultraleap Tracking plugin, the project must be converted to a C++ project. To convert the project:

  • Rename the Plugins folder to Plugin to prevent it being used on loading the project

  • Open your project (.uproject) file

  • Go to File->Add C++ class and add an empty C++ class to the project. It doesn’t matter what it’s named

    https://i.imgur.com/FFCM0ge.png
  • Now, exit your project, rename the Plugin folder to Plugins

  • Right click on your project .uproject file and choose Generate Visual Studio Project Files

  • Open the generated solution (.sln) and build it

  • You’ll now be able to open your .uproject file and edit it as normal.

How do I set up the hand meshes so that the fingers collide with other objects in the scene?

Create a Physics Asset on the hand mesh. Unreal have a guide on how to do this: Skeletal Mesh Actors | Unreal Engine Documentation. See the Collision section for details.

How do I modify a single joint/bone that has been mapped slightly wrongly?

In the anim graph of your anim blueprint, drag a connection out of the Ultraleap Modify Mapped Bones node and add a Transform (Modify) bone node. Now edit the Transform node settings to change whichever bone you want to modify in the skeleton.

https://i.imgur.com/fYomt8w.png

How do I clear a bone mapping back to none in the details view?

Go to the Edit Defaults tab and click the yellow reset arrow next to the bone you want to reset.

https://i.imgur.com/dIjhFEO.png

Why don’t the different hand meshes line up perfectly?

This is due to differences in each imported rigged model and whether or not metacarpal joints are included/mapped.

How do I make my ring finger and little/pinky finger collide with objects in the scene?

By default, the Interaction Engine pawn has collisions turned off for these fingers to prevent accidentally hitting buttons/objects. To enable collisions the Physics asset for the left and right hands must be modified.

  • Open the IELowPloy_Rigged_Hand_Left_Physics asset from InteractionEngine/Pawn/IELowPoly_Rigged_Hand_Left_Physics.uasset

    https://i.imgur.com/VHTrYet.png
  • Ctrl/Multi-Select all the joints for the Ring and Pinky fingers

    https://i.imgur.com/7PHr0TP.png
  • Set the Collision Response to Enabled

  • Repeat for the IELowPloy_Rigged_Hand_Right_Physics asset

In addition, if you want to enable the smaller fingers so that they can push buttons, edit the IEButtonGrabComponent Disabled Bones list and remove Pinky and Ring.

https://i.imgur.com/8ADdDKn.png