Typically when you generate geometry in Dynamo you first define points. However, I have a situation where the best tool for the job seems to be the Line by Tangency node, where you specify a curve and a distance along that curve (as a fraction of the total length). The line this creates has the start point and direction that I want, but is only a unit length. I would like to create a longer line based on this unit length tangent line, and then make use of the start and end points of that longer line to help generate a further Nurbs curve. Is this possible?
Just to say that I have solved this. Switched to a combination of Curve.TangentatParameter (to get a vector) and Curve.PointatParameter (to get a start point), then applied scaling to the vector before using Point.Add to generate a second point.
You could also select a model line drawn in Revit to speed up changes.
Another possible way forward: https://dictionary.dynamobim.com/#/Geometry/Curve/Action/ExtendEnd