wrong dimension after importing step format

Dear OpenCascade experts,

I created 3D models using SolidWorks (also tried SpaceClaim) and then exported the parts in step format.

I then imported the part into netgen (using OpenCascade engine). I found that the dimension is 1000 times larger in all 3 dimensions. For example, the part in SolidWorks was 1m X 1m X 1m. After importing into netgen, I got 1000m X 1000m X 1000m.
Any idea why?

phsieh