Ordinate dimension acting strange

[MikeRoberts]

Using SolidWorks 2014
Ive got a problem using ordinate dimensions & dimensioning to the edge of round tubes.
The base line zero is off a flat edge part & I try dimensioning to the left edge of the infill tubes as shown.
(we do it this way as its quicker for the fabricators to measure to the edge rather than guessing where the centre of the tube is)
All appears ok but if I do a rebuild the dimensions flip to the incorrect side as shown
Even if I do a convert entities to the left hand side of the tube & ordinate dimension to that, after a rebuild it also flips to the wrong side

In the end I added a sketch point coincident to the left edge of the tube & took my ordinates to that.
Yesterday that worked fine even after rebuilding, but today that too is flipping to the wrong side!
Im getting frustrated & cant see where Im going wrong or what else I could try

 

[Outside!]

I believe your issue is caused by the generic SolidWorks issue that when you select a circle, it wants to select what it considers to be the "start" or 0 degrees of the circle. Given this, I can think of a two options.

1. Rotate your tubes 180 degrees about their axis and see if that helps.
2. Create a micro flat of say 0.001" on the edge of the tube you want to dimension and dimension to this flat face