Projecting a line at a slope to a set elevation

What is the best way to project a line using a set slope until it intersects with an elevation. For example, if I have a flowline of a ditch bottom elevated to my desired ditch floor elevations, how do I then create a line parallel to the flowline but at a 30% slope until it reaches a set elevation of lets say 70’ elevation. This elevation would be a flat plane so the slope would lengthen or shorten based on the flowline but the elevation of the offset line would remain at 70’ AND the slope would remain at 30%.

In a corridor or sideslope you can choose Slope to elevation to do exactly this or you can use Slope Designer to do a Slope to elevation also - Slope Designer will do angle xormers better than Corridors and sideslopes



Thanks! Exactly what I needed.