Pre/Post transformations

[pattie]

Could anyone point me to a good source of explanation of what exactly happens when we apply a pretransformation (for example preTrans or preScale, or preRot) or a posttransformation on a link object. What matrices are put into action, what happen to the link object?, etc.
In the following example:
PORT_5DT_USB = 0
sensor = viz.add('5dt.dls')
glove = hand.add(sensor,hand.GLOVE_5DT)
glove.translate(0,1,0)
block = viz.add('box.wrl')
block.translate(0,0,3)
link = viz.link(glove,viz.MainView)
link.preTrans(0,-1.82,-1)
Can anyone explain to me in detail what happens to the link object as well as to the source and destination objects?
I have read the Vizard doc on it, the openGL explanations on transformations in general and I have no problem whatsoever with it. But I still do not understand clearly what the pre and post transformations do.

Thanks for any light on this.
Patrick