Lesson 8 - Complex Rigging

In lesson 7 we discussed how to rig a mesh for rotation offset from 2 global axes. Now we explore how to handle rigging multiple mesh objects together so that they move together and relative to each other.

Please be patient as this lesson is developed!

Example Model

You can download this example model I am using to follow along with this lesson. If you have been following along from previous lessons you will want to re-download this model as some changes have been made to help highlight the differences between 1-axis and 2-axis rigging.


There is a spectrum of difficulty when it comes to complex rigging. It could be relatively straight forward as establishing movement between 2 objects to account for YSFlight's limitation of only one CLA applied to a mesh. It could also be something as complex as making flaps, ailerons and spoilers on a wing that bends (like my 787 model). Each will present different challenges, but by starting with the simpler tasks, we can build the skills needed for the complex

Simple Landing Gear Example

Here we have a simple landing gear model where we will animate the landing gear being raised, but also the wheels rotating left and right to simulate nose wheel steering.

Now YSFlight only lets us have 1 animation on each mesh object, so we will need to split the landing gear mesh into two objects. First lets think of what animations we will use and what parts of the landing gear mesh we will use.

  • CLA 0 (Landing Gear) to raise and lower the whole landing gear assembly

  • CLA 8 (Rudder) to rotate the wheels side to side.

There are several different ways to approach splitting up the mesh object, but what makes sense to me is to separate the wheels into an object that will rotate with CLA 8, and the rest of the landing gear move with CLA 0.

Planning The Parent-Child Relationships

Now we need to consider how the two objects need to be parented. The way I think about this is what object needs to follow the other. For example in this landing gear, I see that the wheels need to follow the rest of the landing gear when the gear is raised and lowered. Similarly, when looking at a wing assembly, the flap or aileron needs to follow the wing as the wing flexes, otherwise the flap or aileron will end up floating in space.

This sets up our parent-child relationships: the landing gear strut will be the parent to the wheels.

Planning Object Centers

Just like with the normal rigging procedure shown in the previous lessons, in this lesson we need to use a technique to properly mark where child object centers will need to be in the parent object mesh. For this we will put a vertex in the parent object at the object center of each child object.