how to change camera location based on object location

Hello

I am trying to move my gluLookAt to an object position (the object's
origin) but I can't do it.
i tried while creating the object to save its matrix:
glGetFloatv(GL_MODELVIEW_MATRIX,mat); and somewhere else in the code
to glMultMatrix(mat), but it seems wrong...

maybe I misunderstand it all?

can someone help?

thanks!