The To Surface extent is an advanced option which allows you to define the extent through a surface. In this case a single target face is selected and its underlying (and possibly unbounded) surface is used as the extent. The underlying surface must fully intersect the extruded profile or an error will result.

Also, note that some Non-Uniform Rational B-Splines (NURBS) target faces cannot be extended. In those cases, the Surface Extension feature may fail if the extension is not fully bounded by the selected target face's surface.

The extent calculation is the same for all material types. The preview will show the direction of the extrusion, but the actual extent calculation is not performed until the feature is generated.

Other Extent Types:

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