I got my extraction with polygon boundary, but I had to "convert" the LAS file to a LAS Dataset. The original LAS had no spatial reference, so I created one (.prj file), which worked fine in the map, but obviously not for the extract tool. With the new .lasd (that has the same spacial reference), the extraction with boundary using the same polygon shape as before succeded. Strange, b/c the new LAS Dataset (.lasd) is just a link container that points to the old .las file. Also strange, that, in contrast to the (conversion) tool's description, I cannot convert between different file types. It accepts only .lasd as output file extension.
But I'm relatively new to the Pro version, so, maybe I'm missing something.
