About the Extrapolate Tool
The Extrapolate tool is available on the Edit tab of the Import DataDoctor ribbon tab. You can also select the relevant geometry, right-click, and access this tool as a shortcut menu option. You can use the Extrapolate tool to extend or shrink the domain of a surface by dragging any of its natural boundaries. You can extrapolate a surface that has no connections defined by a component node. When you select a surface for extrapolation, it is temporarily activated to remove any existing combine or merge connections. If it has a trimmed boundary, the trimmed boundary is temporarily removed and the natural boundary of the surface is displayed. When you exit the extrapolate tool, the trimmed boundary is established again and the combine or merge connections are created again, if possible.
You can select any of the following surfaces for extrapolation:
Any leaf node surface whose parent is not a component node
Any converted procedural surface