The Extension drop-down list in the Expression Builder dialog box (Edit | Expression) becomes available when the item chosen in the ID drop-down list requires the addition of an extension in order to form a usable expression element. The Extension drop-down list displays available extensions based on the item selected in the ID drop-down list.
Suppose you select a feature from the ID drop-down list. The list of possible extensions that can be used to reference data of that feature (such as "X", "Y", "Z", "Diam", "Length", etc.) are then listed in the Extension drop-down list.
Possible extensions include these measured or theoretical data types:
Measured
All – All the values of the feature are assigned to the variable. See the example below.
X – Measured X values of the hits
Y – Measured Y values of the hits
Z – Measured Z values of the hits
XYZ – Measured XYZ values of the hits
I – Measured I values of the hits
J – Measured J values of the hits
K – Measured K values of the hits
IJK – Measured IJK values of the hits
Theoretical
TX – Theoretical X values of the hits
TY – Theoretical Y values of the hits
TZ – Theoretical Z values of the hits
TXYZ – Theoretical XYZ values of the hits
TI – Theoretical I values of the hits
TJ – Theoretical J values of the hits
TK – Theoretical K values of the hits
TIJK – Theoretical IJK values of the hits
F1=GENERIC/POINT,DEPENDENT,CARTESIAN,$
NOM/XYZ,<8,9,10>,$
MEAS/XYZ,<7.98,8.98,9.98>,$
NOM/IJK,<1,0,0>,$
MEAS/IJK,<1,0,0>
ASSIGN/MYFEATURE=F1.ALL
ASSIGN/V1=MYFEATURE.X
ASSIGN/V2=MYFEATURE.TX
V1 contains the value of 7.98
V2 contains the value of 8