From Headus Docs

CySize Measurement Codes

Curves - Magenta

 C = Point to point caliper measurement.
 S = Over surface length
 T = Convex hull tape measure length

Sections - White

 A = Cross-sectional area
 S = Over surface girth
 T = Convex hull tape measure girth

Volumes - Red

 V = Volume
 A = Surface area; doesn't include fill