Assign an arbitrary point position on a shape as the viewing rotation center?

Hi,Gentlemen:
I am new to occ, (still in assessment process)
When experiencing the drawexe.exe (test harness), I had a viewing problem.
Is there a way to assign an arbitrary point position on a shape as the viewing rotation center?
It seems only rotating around (0,0,0) of any shape in the viewer.
What if the bounding box of the shape does not contain (0,0,0), on the contrary, it is very far from (0,0,0)? (such as the back-door of a car:
the center of a car model is usually between under the two front head-lights)
When i rotate the view, the back-door shape just swing out of the view.
How can i prevent this?
Please give me a hint? (using what tcl command,or what c++ functions?)
(i can understand both)