STEP 1: DIGITIZING
1. Digitize vessel as an open entity (do not close to make a polygon).
2. Draw midline based on vessel diameter.
Set COORDS to 2, to measure distance from rim (radius) and angle (180); and use F8 (ORTHO) to have straight lines.
PLINE: start on point 1; move left watching coordinates (lower left),
3. TRIM overshots of profile and line.
Continue to step 2