# Mappings Right click anywhere in the content browser and under the category Existent choose Hand Bone Mappings.

Next create a Body Bone Mappings asset.

Finally create a Tracker Mappings asset.

## Mappings skeletal mesh properties All bone mappings assets, for the exception of the tracker mappings, require to specify a skeletal mesh and a skeletal mesh rotation delta. The skeletal mesh asset is used to both preview the bone mappings in the viewport and to work with the player skeletal mesh at runtime. Both the player blueprint skeletal mesh and the skeletal mesh specified in the bone mappings must be based on the same skeleton.

The skeletal mesh rotation delta is the property which allows to specify the relative orientation for a skeletal mesh bones. Skeletal meshes can come with different bone orientation from each other, the existent body system works on the X axis pointing forward, the Y axis pointing right and the Z axis pointing up. This means that when using a skeletal mesh such as one based on the UE5 skeleton we need to rotate the mesh by 90 degrees on the Z.

Notice how the mesh faces towards the Y axis. The same applies for the UE4 skeleton. Below you can see the custom asset downloaded from the marketplace which works with a skeleton based on the UE4 skeleton.

And finally, the Mixamo skeleton shows a very different bone orientation with the Z axis pointing forward, the Y axis pointing downwards and the X pointing to the left. Following you can see the axis orientation as well as the required skeletal mesh rotation delta value required to fix the skeletal mesh orientation.