aVersionOfReality@AversionReality
The @getfondant Blender Custom Normals Addon version 2.1.0 is almost ready. For this update I've returned to the Laplacian Smooth modifier (in the $0 version). There's a lot of big improvements based on my testing and some problems users found. One of those is a classic problem in Laplacian Smoothing: Instability!
For various reasons, certain areas of the mesh can end up with very small or large values that cause oscillations. In Position smoothing, this causes the mesh to explode. For Normals, we get crazy banding or checkboard shading.
This happens at high iterations and high strength. The solution is to lower the strength. Sometimes 0.9 will do it, but sometimes you end up down at 0.5. That works, but then you have less smoothing. Now you need more iterations again to get to the same amount and it gets slower. And more iterations = more risk of instability.
I've implemented Momentum Smoothing, which helps prevent weird movements and oscillations by keeping some of the movement from the previous iteration. This is technically less precise, but we don't care for smoothing toon shading. It works so well that you not only don't need to turn down the strength, you can even turn it up to 2 or even 3! That means less iterations, or really crazy amounts of smoothing!