Computer has just crashed for the fifth time today. There seems to be a problem adding a surface curvature relation to a spline. Have two surfaces that I join with a spline. Select a surface, edge and spline to create the curvatre relationship. Did this on both ends of spline. Computer crashed repeatedly.

For one spline on some occasions I also added a tangent relation to make it tangent to a line on the surface.

Model attached. See the last sketch in the feature tree.