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What does this true position mean?

I don't know what this true position on the hole is constraining. Bolt circle diameter or orientation of the hole maybe? Trying to determine if I need to measure the hole as a cylinder. Appreciate the help.

Parents
  • PCDMIS takes your directional values in your case Y and Z and combines them to give you your TP. TP Allows for a Bonus positional tolerance based on the size of the feature you are measuring. (See Hole_3)


    What does TP stand for? I also don't see how the TP can be more than the combined y and z deviations.
Reply
  • PCDMIS takes your directional values in your case Y and Z and combines them to give you your TP. TP Allows for a Bonus positional tolerance based on the size of the feature you are measuring. (See Hole_3)


    What does TP stand for? I also don't see how the TP can be more than the combined y and z deviations.
Children
  • Position deviation is calculated in 3 dimensions using the formula

    Position = 2 • sqrt(x_deviation^2 + y_deviation^2 + z_deviation^2)

    The formula is derived from the Pythagorean Theorem. A reasonable approximation for the position deviation is

    Position ~ 2 • max(x_deviation, y_deviation) + 1/2 • min(x_deviation, y_deviation)