Introduction to Alembic

1. Introduction to Alembic

This tutorial has been verified using Unity 2019.4 LTS and Alembic 1.0.7.

Character animation in Unity is usually done with the FBX file format. This poses a number of limitations for character skin weighting, as a single vertex can have only up to four bone weights in Unity 2018.3 and earlier versions. This restricts how complicated a character’s rig can be.

Another common animation format is Alembic. It’s fairly standard in the TV and film industry due to its “what you see is what you get” nature. Often, animation studios will work with live rigs during a production, and once an episode is completed, they will bake animations to Alembic to guarantee they won’t be affected by software changes.

Some 3D modeling software such as Blender also can export to the Alembic file type (.abc), which preserves any animations created within blender. The models with their associated animations can then be imported into a Unity project.

2. For more information

You can find additional information about Alembic on the Alembic website (www.alembic.io) and in the Unity Manual, Alembic section.

3. Package Manager

You will have to open up Unity’s Package Manager to install Alembic into your project (Figure 01).

Figure 01: Unity’s Package Manager

4. Alembic Examples in Unity

Two examples of projects that use Unity’s Alembic playback include Adam Episodes 2 and 3 from Oats Studios and Cycles from Disney (Figures 02, 03).

Figure 02: For more information on Adam Episodes 2 and 3, by Oats Studios, visit https://unity.com/madewith/adam

Figure 03: For more information on Cycles, by Walt Disney Animation Studios, visit https://unity.com/madewith/cycles

For more information about how Oats Studios used Alembic in the ADAM projects, check these two blog posts that discuss their process:

• Alembic Support

• Cloth Simulation