Tape measure tool problem

I am having problems with the tape measure tool. Using Sketchup Pro v. 8 on a 2007 Macbook. I use the tape measure tool a lot, but recently when I place it and focus in, it seems to bend. The series of screen shots show the tape measure line placed to the left of a line of circles (representing rebar). As I focus in, it moves around until it is to the right of the circles.

This screenshot shows the tape measure line I drew (it has an arrow pointing right at it to the left of the shot.

Focusing in… notice the fourth circle down, the line appears to bend away.

More… Now the line is to the left of the circles except for the bottom circles, in which the line is more or less centered on the circle.

Finally… back to where it should be. The circles are perfectly lined up, have redone this a number of times in different ways and the result is the same, so please don’t ask the obvious question.

Another oddity… Had the tape measure lines drawn up, and just for the heck of it, used the boundaries to draw a square. I have not, in more than five years using Sketchup, drawing houses and furniture, ever seen this. Help?

Two ideas…

Switch off Distance snapping in Model Info > Units

Twiddle with your OpenGL settings in Preferences…

Is it possible to post your model.
I made linear array of 1/2" dia, circles and could not duplicate your problem :smiling_imp:

Thank you, the OpenGL settings was it. After it was fixed, I remember I had to reinstall SU8 a few weeks ago and forgot to uncheck the setting.