It is possible to measure the cross-sectional surface in Acoustic Rhinometry. For that purpose, select a test result, and use the right mouse button to edit the result.

Edit Result

Now click on the position where you want to measure the cross-sectional surface. A dotted line appears to demarcate the area and the surface appears in the top row (left, total, right).

Rhinometry Surface

This feature is not available in the webviewer.