Chapter 14: Making a Custom Rig for Our Alien Plant with Control Rig

In the previous chapter, we completed a more complex skeleton for the robot. Now we'll move on to the next stage of creating an animation-friendly rig in Unreal Engine (UE). Creating a skeleton and skinning it are the first steps toward making our 3D model or character animatable. We will learn how to add controllers that make it easier for animators to animate it.

With good controllers on top of a skeleton, it makes it possible for animators to edit, organize, and refine animations in a much more effective way. The general process of setting up a more complex 3D model to be animatable is called rigging it.

Rigging has three general steps:

1. Creating a skeleton
2. Skinning the 3D model to the skeleton
3. Creating controllers to drive or control our skeleton, otherwise called creating an animation rig

Until recently, there weren't any effective tools in UE to create and manage animation...

Technical requirements

The following are the technical skills and software you need to complete this chapter:

• A computer that can run basic 3D animation software.
• You need to have Blender installed for free from https://www.blender.org/ (at the time of writing). The Blender version used in this chapter is 3.1.2, but some older and newer versions will also work.
• A basic understanding of how to navigate the 3D user interface. If you skipped ahead, this was covered in Chapter 1, An Introduction to Blender's 3D Modeling and Sculpting Tools. If you want further tutorials on how to use Blender in depth, https://www.blender.org/support/tutorials/ is a great resource.
• You need to have installed UE5.
• Have a basic understanding of how to navigate the UE 3D user interface. If you skipped ahead, this was covered in Chapter 6, Exploring Unreal Engine 5.

Finally, you should have completed Chapter 12, Alien Plant Skinning in Blender.

The files related to this...

Introduction to the Control Rig Editor

The Control Rig Editor is where you make the animation rig and its controls inside UE. At the time of writing this book, it's still very much in development, but I'm sure the capabilities will expand over time, as well as its simplicity and optimizations.

First, we need to activate and load the Control Rig plugin in UE since it's not currently loaded by default. The Control Rig Editor can be a very powerful tool, with many features that are outside the scope of this book to cover. However, the basic parts that we will learn about will enable you to rig and animate most things in UE5.

Loading the Control Rig tools in UE

Control Rig in UE5 is a plugin. Plugins are just extra functionality in the software. Sometimes, they don't load by default to make the program run lighter and load faster. With plugins, you have the ability to just load what you need. To load the Control Rig tools plugin, execute the following simple...

Creating basic Control Rig controllers

The Alien Plant only needs a very simple forward kinematics (FK) rig setup. This sounds very complicated but FK is just basically the same parent/child setup we did with the skeleton itself. The child bone follows the parent all the way down the chain. Our FK animation rig controllers will behave in the same way.

Note

In animation, there are two main ways to control a joint: FK and inverse kinematics (IK). We will cover FK in this chapter and IK in Chapter 15, Creating a Control Rig with Basic IK Controls for the Robot in UE5.

Let's create our controllers. First, we'll create a few simple control shapes.

Creating two simple control shapes

We'll start in a very simple way and create two control shapes that will control our skeleton bones. Control shapes are the things we select in the 3D Viewport to move our character in the scene:

1. Right-click on an empty space in the Rig Hierarchy panel and select New | New...

Controlling the Alien Plant skeleton with the controllers

The final step in creating the Control Rig for our Alien Plant is to get the controllers to drive/control the skeleton. The Control Rig system can be used to create very complicated rigs that are beyond the scope of this book. The Control Rig system uses a series of nodes that can be linked together in a visual way to drive the behavior of our Animation rig.

For a simple FK, we just need a few basic nodes in our Rig Graph panel, as follows:

• Forwards Solve: This node simply starts the flow of the rig node logic and is at the start of any Control Rig we build.
• Set Transform - Bone: This is typically used to "set" or receive the transform values from the controller and apply them to the bone.
• Get Transform - Control: This is typically used to "get" the transform values from the controller and feed them to the bone.

If this sounds complicated, don't worry. It is simpler in practice...

Summary

In this chapter, we learned how to correctly export our Alien Plant from Blender and import it into UE. We learned how to activate the Control Rig plugin and navigate its basic interface. Finally, we built a basic FK rig with the Control Rig system. With this knowledge, you can now build FK animation rigs in a UE5 Control Rig. This means you can build FK animation rigs for all kinds of different animated objects and characters for your scenes.

In the next chapter, we will build a Control Rig for our robot that will include IK.