Getting 0 Volume for object I am trying to calculate the volume of a 3D scanned object using the 3D Print add on. 

The object was captured with a structure sensor/ipad and then imported to Blender (version 2.79). The scanned model is of a small box (~8x3x6cm), so simple at this stage. As the object didn't have a base when imported, I followed instructions from this web site to add a base using re-mesh and then smoothed. 

I activated the 3D Print add on and changed to metric units with cm selected. I then asked the program to calculate the Volume of the object in the 3D Printing tab. The volume comes up as 0.0 cm³. 

There are dimensions in the right hand side panel under "Transform" of 81.38x23.00x59.80 um. Again this isn't quite right as the dimensions should be about 80'000x30'000x60'000 um given my physically measured box. 

Any help in getting the volume calculation function to work would be appreciated.
μm is Micrometre, one thousandth of a millimetre (0.001 mm or about 0.000039 inch).
If you try to calculate the volume of 81.38x23.00x59.80 um it will be around 0,0001mm3 or 0,0000001cm3 that is to small and rounded.

If you want to measure object in imperial units you need to go to scene tab and select this unit system from presets: