• View >> Set Trackball Center command sets the rotation center to a user-defined position on a shell.

Step   

Execute View >> Set Trackball Center command as follows:

1. Select View >> Set Trackball Center from the menu or click the icon from the View toolbar.

2. Pick a point on a shell to serve as the new rotation center. On RMB menu, User can select point entity to be center of trackball

 

Point : Any point on polygon face

Vertex : Scanned point

Ref.Point : User made Ref.Point 

Point On Surface : any point on NURBS surface.

Point On Curve : any point on NURBS curve.

• When you rotate a shell or model by Virtual Trackball or Shell Trackball, the rotation center is changed to the picked point.