We can do more with Actors
than just play animations on them. We can also attach other NodePaths
to specific joints in an Actor
so that they will follow that joint wherever it moves. This technique is often used to put objects in a character's hands. For our game, we'll be using it to attach the discs and turret to our cycle.
This technique works well for us because we want to change the rotation of the discs and turret. For that to work correctly, the models need to have the points they will rotate around at (0, 0, 0)
in their own coordinate system. That means we can't reposition them in the modeling software, as we did with the static parts of the cycle such as the power plant.
Instead, we'll load an Actor
that only contains three joints. The joints are located at the positions where we want to place our discs and turret. If we attach the Actor
to the cycle's model, we can use the joints as mounting points for the discs and turret.