I see. As an alternative, could we have an option to have a number of 'draft' rebuilt curves generator on either side of one made from user-defined parameters. Say a -2, -1, 1 and 2 drafted on either side of a '0' that the user would have input ? I guess all this would take would be multiple executions of the same Rebuild routine; The tricky part would be to have an elegant way to select the desired curve out of the 5 (or whatever) generated.

But I am prone to over-engineering, I know. :)

Jean-Paul