Fillet Order of Operations

Fillet Order of Operations

Reference Videos

These videos utilize applications other than Plasticity for demonstration purposes, but the concepts can also be applied to operating Plasticity, so they are provided here for reference.

"Alias Theory 9 - Fillet Order of Operations" - 3D Design Academy


This tutorial focuses on the "order of operations" for applying fillets in 3D design. The tutorial emphasizes the importance of applying fillets from large to small and discusses how to handle special cases where equal-sized fillets are required.

Basic Rule: Large to Small

The basic rule of thumb is that you almost always want to go from large to small when applying fillets. For example, I have a cube and I'm going to put fillets on all sides. I'll start with the larger fillet of 200 units. This makes the process easier and more effective.

What Happens When You Reverse the Order

Let's see what happens when we reverse the situation. If I start with a smaller fillet of 100 units and then try to apply a 200-unit fillet, the design doesn't build well. The corners end up looking weird and are essentially useless.

Handling Special Cases: Equal-Sized Fillets

Sometimes, designers may want equal-sized fillets on all surfaces. In such cases, evaluate the angles between the surfaces. Apply the fillets first to the surfaces with larger, more open angles. This usually results in a much better design.


Understanding the correct order of operations for applying fillets is crucial for achieving a clean and effective 3D design.