What are the advantages and disadvantages of using morph target animation over skeletal animation?

1 What is morph target animation?

Morph target animation, also known as shape interpolation or blend shapes, is a technique that uses a set of predefined shapes or poses for a 3D model, and interpolates between them to create smooth transitions and variations. For example, you can create different facial expressions for a character by adjusting the positions of the vertices on the mesh, and then blend them together to animate the character's emotions. Morph target animation is often used for subtle and detailed movements, such as lip-syncing, eye blinking, or muscle deformation.

2 What is skeletal animation?

Skeletal animation, also known as rigging or skinning, is a technique that uses a hierarchical structure of bones or joints to control the movement of a 3D model. The bones are attached to the mesh by weights, which determine how much each vertex is influenced by the bone's rotation or translation. For example, you can create a skeleton for a human character, and then animate the bones to make the character walk, run, or jump. Skeletal animation is often used for large and complex movements, such as body mechanics, locomotion, or combat.

3 Advantages of morph target animation

One of the main advantages of morph target animation is that it can produce very realistic and nuanced results, especially for facial animation. By using morph targets, you can capture the subtle variations and expressions of a character's face, and make them more believable and engaging. Another advantage of morph target animation is that it does not require a complex rigging system, which can be time-consuming and challenging to create and maintain. Morph target animation is also more compatible with motion capture data, which can be used to record and apply realistic movements to a 3D model.

4 Disadvantages of morph target animation

One of the main disadvantages of morph target animation is that it can be very memory-intensive and performance-heavy, especially for high-resolution models. Each morph target is essentially a copy of the original mesh, with different vertex positions. This means that you need to store and load multiple meshes for each character, which can increase the file size and the rendering time. Another disadvantage of morph target animation is that it can be difficult to edit and modify, especially for complex and dynamic movements. Morph target animation relies on predefined shapes, which can limit the flexibility and creativity of the animator. If you want to change or add a new pose or expression, you need to create a new morph target and blend it with the existing ones.

5 Advantages of skeletal animation

One of the main advantages of skeletal animation is that it can be very efficient and versatile, especially for low-poly models. By using bones, you can control the movement of a large number of vertices with a few parameters, which can reduce the memory usage and the rendering time. Another advantage of skeletal animation is that it can be easily edited and modified, especially for procedural and interactive movements. Skeletal animation allows you to manipulate the bones directly, or use inverse kinematics, physics, or scripts to generate realistic and dynamic animations. You can also reuse and adapt the same skeleton for different characters, which can save time and resources.

6 Disadvantages of skeletal animation

One of the main disadvantages of skeletal animation is that it can be less realistic and expressive, especially for facial animation. By using bones, you can only control the movement of the vertices by rotating or translating them, which can result in unnatural or stiff deformations. Another disadvantage of skeletal animation is that it requires a sophisticated rigging system, which can be complicated and tedious to create and maintain. Skeletal animation involves setting up the bone hierarchy, the weight painting, the constraints, the controllers, and the drivers, which can be prone to errors and glitches.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?