Posted: 14 May 2008 at 12:47pm | IP Logged

There are a number of surface features that show up as "Surface id xx" in
the model tree.  Is it a legacy file?  Info -> Feature says?  Are you sure
the existing surfaces (either the feature or geometry) are not on a layer
that's been Hidden?

Unless you suspect some particular reason not to, I'd just go with whatever
will work (i.e. the Extrude) and Hide.

Posted: 14 May 2008 at 1:03pm | IP Logged

Under the Insert menu Sweep, Blend, Swept Blend, and Helical Sweep have different feature creation options. The surface feature creation option gives a default name of "Surface id xxxx" for each of these types. If you select protrusion you will see a "Protrusion id xxxx". The options extude, revolve, variable section sweep, boundary blend, etc. default name of "(feature type) x". As far as the surface being invisible it is probably hidden in the model tree or the layer that contains the feature is hidden.

For a simple example sketch a straight line, once that feature is created select Insert>Sweep>Surface, choose select trajectory from the menu and select the curve you created, select open or capped ends, and sketch a section.

Posted: 14 May 2008 at 1:13pm | IP Logged

I bet it's a pre-WF part.  The features had a different naming convention then.

I'd also bet that they are on a layer that's blanked.  Remember, putting a solid feature on a layer and blanking does not hide the feature, although it will hide 2D items like axis that are a part of the feature.  For a surface feature, however, putting the feature on a layer and blanking it hides the surface.