Import DataDoctor > Geometry Creation Tools > About the Boundary Blend Surface
  
About the Boundary Blend Surface
When you import data from other CAD systems, the quality of the imported data may be poor. Some surfaces may be missing in the imported feature or the imported surfaces may be corrupt. In such cases, you can use boundary blend surfaces to create the missing surfaces or construct replacements for the corrupt surfaces. You can use one-sided edges, UV-curves, 3D curves, datum points, or vertices to define the surfaces. New boundary blend surfaces are created as base-level leaf nodes. The creation of boundary blend surfaces is non-associative and non-parametric.
Click Boundary Blend on the Create tab to access the Boundary Blend tool. With the Boundary Blend tool, you can create a boundary blend surface between reference entities that defines the surface in one or two directions. The first and last entities selected in each direction define the surface boundary. Adding more reference entities, such as control points and boundary conditions, allows you to fully define the surface shape.
In each direction, reference entities must be selected in consecutive order. However, reference entities can be reordered.
For blended surfaces defined in two directions, the outer boundaries must form a closed loop. This means that the outer boundaries must intersect. If the boundaries do not terminate at the intersection points, IDD automatically trims them and uses the relevant portion for the construction of the boundary blend surface.