Lesson 8 -  Complex Rigging

This lesson is still being developed. Please check back later when the lesson is finished.

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.

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.

Introduction

There is a spectrum of difficulty when it comes to complex rigging, ranging from the simpler (like the example shown in this lesson) to the more complex (like my 787 wing fold animation). In YSFlight we have to account for the limitation of one CLA animation applied to each mesh which drives us to work arounds in order to make things appear closer to how real-life aircraft move. Each situation where you need to utilize the techniques shown here will be different, but by starting with simpler tasks, we can build the skills needed to work on complex models and effects.

When we want a component to move with two animations, we have to use parent-child relationships between objects, where each object has a different CLA animation applied, and combining to form the final combined visual effect the modeler is trying to achieve.

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.

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.


Visual Animations:

When dealing with some animations to make a component appear and disappear, our hands may be tied with respect to what animations to apply to what mesh object. If you need some thing to disappear, generally speaking that animation CLA needs to be tied to the main mesh object and any animations that are going to move the object need to be tied to the supplementary Empty Mesh objects we will learn about later.

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.

Based on how the landing gear should move, we will set the landing gear strut as the parent object and the wheels as the child object. That way when the landing gear is raised and lowered, the wheels will move with the strut. 

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 in order to make our lives simpler within Blender. As this vertex is not rendered in YSFlight, nor does it add much of anything to the overall filesize of our DNM model, we can leave it as-is in order to make later modifications even easier.