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.

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.

If the resulting boundary blend has more than a single surface patch, a component quilt node is created with the Solid option not selected. If the resulting boundary blend only has a single surface patch, it is a simple leaf surface node named Surface.