Surface area in ST8

[ Edited ]

Hello Edgers


I would like to know the surface area about an assembly in my ST8.
I've already make a simplify model with the Visible faces, and then save that as a part.
When I access Physical Properties, the Surface area appear like the image below in a negative value.

I did this on ST6 and it worked, but now that I own the ST8 I can't do it any more.


Can anyone help-me to solve this?