Surfacing > Creating Advanced Surface Features > Creating Boundary Blends > Example: Blended Surface
  
Example: Blended Surface
Create a surface by blending curves in one direction
Original curves:
Select the curves in order, either 1-2-3 or 3-2-1:
Resulting surface feature:
Create a surface by blending curves in two directions
Original curves:
Select the curves for the first direction in order, either 1-2-3 or 3-2-1:
Select the curves for the second direction:
Resulting surface feature: