#76 filling bottom of 3D-scanned object?

[Michel Albert Audette]

Hello,
I have a 3D-scanned object that was obtained from a Structure Sensor. Invariably, there is a large hole at the bottom. What is the right filter to close this hole? The hole filling does not seem to address it, or is this a threshold issue? The only thing that I've seen so far is the Convex Hull, but it blurs out the details of the scan, which is deleterious to the model.
Thanks for your kind support.
Michel