While planning out the movement of the main character we had a little roadblock when trying to decide how to implement root motion in three dimensions. We had experience utilizing a 2-D blend tree to interpolate between root motion animations of a character that could move in two dimensions but the addition of the ability to swim up and down made us rethink our approach. We searched for a possible 3-D blend tree but unity does not have that feature (I wonder why?). Perhaps in the future we might create a Unity editor tool for 3D blend trees ourselves. However, the simplest solution we found was to use animation layers. We could have a 2D blend tree in the characters base layer and a 1D blend for up and down movement in a lower additive layer. This would allow the character to move forward, backwards, side to side, and also up/down through adding the differences of those animations to the base layer. We have yet to test this in Unity but theoretically this should work. In the future, I will make another blog post about the problems we faced in application(if any) so look out for that!