Look cadplayer, this angle is tolerance angle, not angle of starting segment... As I said if top projections of imaginary connections of resulting polylines are close to straight line, that angle should be near 0.0 degree - 0.0 isn't allowed so you must enter 1.0 or some small angle, and if projections are curving, like in my posted example then you should enter angle close to difference angles of adjacent segments of imaginary projection polyline...