Chapter 12: Alien Plant Skinning in Blender

In the preceding chapter, we created a skeleton armature for our Alien Plant. Using a skeleton with a 3D model, you need to tell the 3D software what part of the model needs to follow which joints. You also need to tell the 3D software how much it influences that part of the model, particularly the blend between different joints. This process is called skinning. It is much like the way your forearm skin follows your forearm bone and the elbow skin is a blend between your forearm and upper arm bones. Skinning is also commonly called skin deformation.

All this might sound very complicated to do. Indeed, to do the skinning of a full human or animal character, for example, can be very challenging and time-consuming. However, in this lesson, we will start with the very basics, which are easy to master and will enable you to achieve a lot in your 3D scenes. In this chapter, we will cover the following:

• Introduction to skinning in Blender...

Technical requirements

You need to have Blender installed, which can be installed for free from https://www.blender.org/ (at the time of writing). The Blender version in this chapter is 3.1.2, but some older and newer versions will also work.

You will also need 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 in-depth tutorials on how to use Blender, https://www.blender.org/support/tutorials/ is a great resource.

The files related to this chapter are placed at https://github.com/PacktPublishing/Unreal-Engine-5-Character-Creation-Animation-and-Cinematics/tree/main/Chapter12

Introduction to skinning in Blender

As I explained in the introduction to this chapter, skinning is where we tell the 3D model how to deform and follow the bones. We need a way to tell the 3D software what part of the 3D model we want to follow, which bones, how much, and how to blend between them. We call this skin deformation, generally. Skinning is applied to the vertices of the 3D model. Editing the amount a vertex is deformed by a bone is called editing its weights.

There are mainly two kinds of skin deformations:

• Rigid, where the vertices follow the bone at 100%.
• Blended, in which two main areas of the 3D model meet and are deformed by two different bones. The blend is to have a smooth transition between them, such as an elbow or a knee.

It is the blended deformations where things can get tough in certain circumstances where one vertex can be influenced by not just two, but three, four, or even five bones at the same time. A typically difficult area to skin...

Skinning the Alien Plant mesh to the skeleton

Now, for the final part of this chapter, we'll finally get to skin our alien plant. Your plant might be different from mine if you modeled it yourself in the previous chapters. Your skinning results might be different from mine and might require more editing. Since you have learned the basics of skin weight painting in this chapter, you should be able to fix any problems that come up. If not, load the file provided (https://github.com/PacktPublishing/Unreal-Engine-5-Character-Creation-Animation-and-Cinematics/blob/main/Chapter12/EndOffChapter11_Results_AlienPlant_withSkeleton.blend)

so you can proceed with the rest of the instructions.

Skinning the Alien Plant

We'll use the skeleton we created earlier and skin our Alien Plant to it. To do so, follow these instructions:

1. Load the file you saved earlier with the Alien Plant and the skeleton.
2. Once the file is loaded, just like in the previous section, we will...

Summary

In this chapter, you've learned how to do skinning and how to edit skinning with weight painting, and finally, you have skinned your Alien Plant to your skeleton. If you enjoyed this process, this is the very first step in becoming what they call a character rigger in the industry, a specialized job for people who enjoy skinning and rigging characters for games and movies. Even if this process is not one of your favorites, it's important to learn how to do it if you want to create new animated content on your own as a generalist.

In the next chapter, we will use what we have learned so far and create a skeleton and skin for our robot character.