T values indicate true deviation from nominal cad surface. Sometimes they are + for extra material and sometimes they are - for minus material if you have the correct vector selected.
Yes this is how i was thinking but it can get confusing.
I have an internal radius +.015/-0 so it's T-value is +0/-.015 (no extra material aka smaller, .015 material off aka bigger).
Not enough coffee this morning and I needed a sanity check lol.
T value works also witout cad !
It's the projection of the measured point along the theo vector from the theo point.
ASSIGN/T_VAL=DOT(PT1.XYZ-PT1.TXYZ,PT1.IJK)
You can also calculate the T values on a scan (if you know the theo !)
ASSIGN/T_VAL=DOT(SCN1.HIT[1..SCN1.NUMHITS].XYZ-SCN1.HIT[1..SCN1.NUMHITS].TXYZ,SCN1.HIT[1..SCN1.NUMHITS].TIJK)
T+ is + material, T- is -material, so, as you said, a scan in a hole with T_values <0 is larger than the theo diam.
Easy to make a mistake here!
