This feature takes advantage of original line art chain which is a continuous long chain, instead of splitting it at each occlusion change, this function tolerates short segments of "zig-zag" occlusion incoherence and don't split the chain at these points, thus creates a much smoother result.
No additional sliders for this threshold, the value follows chaining threshold and it seems to do a pretty well job (because they basically determines the same near-field search radius). This way we won't have more confusing values to adjust.
This function only has a checkbox for preserving details, when it's on then the "zig-zag" will be preserved as-is, only the occlusion level will be tuned to the same as on the rest of the chain, when off then those incoherent vertices are removed and creates a zig-zag-free stroke, depends on how the user would like to express those twisted regions, both ways can find their use in certain scenarios.
