I have a problem with Inventor pro 2013 rounding of the area moment of inertia to zero (region properties). For example if I create a new sketch and draw a 1 mm x 0.5 mm rectangle and measure the area moment of inertia it will be 0 for one of the pricipal axes. If I change the rectangle to 1 mm x 0.6 mm it doesn't round it off. Seems like there's a problem with the precision in the calculations somehow.
I have tried to change the document units to microns but the same thing happens.
What is wrong? or more importantly is there a way to make inventor do this calculation correctly?
I've test out your issue as discribed and in my case the data updates with the changes. Please check and see if you have SP1.1 loaded and let us know it can be found at http://usa.autodesk.com/getdoc/id=DL20442029