Auto deviation letters

[psalm2]

ver 3.52

Sometimes the T value will give the incorrect letter. Is it something Im doing wrong or is it in the software version.

DIM LOC27= LOCATION OF POINT MFP1 UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
X 3870.655 0.700 0.700 3870.655 0.000 0.000 ----#----
Y -533.730 0.700 0.700 -533.876 -0.146 O 0.000 ---#-----
Z 1515.025 0.700 0.700 1515.099 0.074 H 0.000 ----#----
T 0.000 0.700 0.700 0.164 0.164 I 0.000 -----#---


The Y shows it OB which is correct and the T shows IB

[Glenn]

The answer is correct. The point is farther negative in Y, therefore it is shown as negative deviation in the Y axis. The vector, however, is positive (meaning the point showed + material) so the T (vector) deviation is positive. It can be confusing at times, but remember that directions of axes does not mean direction of material.

[psalm2]

Glenn
How could the T value be correct if the Y value showes it to be OB which is correct. The T value shows it to be IB which is not correct.

[Glenn]

The T value shows it outboard. It is positive. That means that the surface is too far positive (outboard) some direction, which is a positive surface vector. Not coordinate direction, surface vector. Clear your mind for a moment and try to follow this: Think of coordinates as directions like east (X+), west (X-), south (Y-) and north (Y+) on a map. That is what X,Y and Z are, essentially, just coordinates like on a map. Now, if the west side of the Rocky mountains exploded outward, the explosion would be in a positive vector from the mountains. That is positive direction vectorwise, but negative direction coordinatewise (X-). If the west side of the mountain collapsed inward, the surface vector would be more negative (-T), but the change in coordinates would be positive (more easterly, or X+ direction). Bottom line: T is not a geographic type direction, it is a part surface direction. I hope this helps clear the fog a little...

[psalm2]

Glenn if you look at my example y shows this point O meaning Outboard farther away from the center the T shows it I meaning Inboard which is not correct.

[Glenn]

Sorry, I was overlooking the deviation letters. I never use them, so I have no answer for that. I constantly struggle with teaching customers why the T doesn't appear to agree with the coordinates, so I gave my typical lesson outline. The T is correct, of course, but I agree the I should be O. I tried those once before and I think I also questioned the results. It sounds like a glitch to me, too.

[rebeldude]

I've never had that problem, but I never used V3.52 either. It may be the version