Distortion falloff and protected area

[Hawkers]

Can we get some parameters to fine tune the width of the protected area and the distortion falloff? These are the names of the parameters in Stickman's Ultraview Nuke plugin.

[Niek]

Adding some extra parameters is the smallest issue ;) Integrating them into the filter generator is the difficult part. Do you have any pointers how these 2 variables relate to the generated x values of the filter?