Actual Length vs Dimension Value

[PatrickMacMahon]

Hi,  Just upgraded to AI 2018 and having problems with Sketches and Assemblies which has not happened before.

When I dimension a line, the actual length is different to the entered Dimension value when measured using the Inspection tool.  

The difference is very small but great  enough to prevent Mating in the Assembly phase.  

This also occurs with the Equal command where to lines of supposedly equal length are very slightly different when measured separately.

Have I got a setting wrong or is it something more exotic ?  Picture below

[JDMather]

Can you attach file here that illustrates this issue?

[johnsonshiue]

Hi! I can think of two reasons why it behaves this way. 1) The measurement is referencing geometry different than the actual dimensioned geometry. 2) There is minor numerical noise in displayed measurement due to high precision setting. You are using 6 decimal places to display the measurement. #2 reason does not make sense. Sketch precision should be up to 10E-9mm. I need to see the files in order to tell where the problem is.

Many thanks!