How It Works | Linear Blend Skinning
Linear Blend Skinning is probably the most common algorithm used to deform a mesh using skeletal structures. It’s used in game engines such as Unreal and Unity and it’s default deformation method in DCC applications such as MODO.
The main advantage of Linear Blend Skinning is the fact that it is not computationally intensive and still provides acceptable deformations in a good range of situations. It also supports all basic transforms which means that the mesh geometry can be not only rotated but also translated and scaled.
That's not to say that LBS doesn't have any drawbacks. The main issue is loss of volume in bent areas and a so called candy wrapper effect that happens when skeleton joints are twisted.
In this tutorial we will build a simple rig in Foundry MODO that replicates what Linear Blend Skinning algorithm does for a single vertex. We will use simple cylinder geometry and 2 joints that will act as transform effectors. This will hopefully help you in understanding the algorithm and its limitations better.
Even though the rig will be built in MODO you can still follow the tutorial if you're not MODO user. Simply skip Part 2 (that one is MODO specific).
- Part 1 presents the Linear Blend Skinning algorithm explanation.
- Part 2 covers building a rig in Foundry MODO that replicates what Linear Blend Skinning algorithm does for a single vertex.
- Part 3 is short discussion on Linear Blend Skinning issues and possible solutions to these issues based on the interactive rig built in Part 2.