Blend

Perpendicular

When Continuity=Tangent or Curvature, allows you to blend a curve to a surface edge perpendicular to the surface with continuity.

AtAngle

When Continuity=Tangent or Curvature, orients the direction of the blend curve other than perpendicular to the edge. You will usually need reference geometry to select since you cannot type in an angle value.

In this case, to make a curve to use in the Sweep2 command with vertical ends but not be a trimmed surface, snap the angle to the upper endpoints of the vertical reference lines.

Hold Shift to restrict the angle direction by ortho but keeping it tangent to the edge curve.

In the video, the red curves are blended at the angle determined by the vertical blue construction lines.

Continuity

These options set the continuity for each end of the blend.

Continuity 1 / Continuity 2

Sets the continuity option between the blend curve and the input curves or edges.

SubCrv

Type subcrv to select part of a curve as input.