<P>
My answer might not be very relevant but what you are suggested is already implemented through ivtk a tools available with tvtk.<BR>
<BR>
See more details about tvtk at :<BR>
https://svn.enthought.com/enthought/wiki/TVTK<BR>
<BR>
<BR>
<BR>
>>Hi everybody,<BR>
<BR>
>>As I already posted, I'm using VTK to develop a visualization and 3D<BR>
>>editing software, and I would like to add a nice feature that I found<BR>
>>in other similar software. That is, I'd like to show a set of 3D axes<BR>
>>in a fixed position of the display; their purpose it's just to show<BR>
>>the xyz directions while the user explores the scene.<BR>
<BR>
>>I tried to implement a MouseMove observer that updates the scale and<BR>
>>positon in real time, but the result is not as good as I wish. I also<BR>
>>searched a lot in this list, but found nothing useful for my >>purposes.<BR>
<BR>
>>Is there someone who can kindly suggest me a feasible way to achieve<BR>
>>this result?<BR>
<BR>
>>Tkanks in advance.<BR>
<BR>
>>Bob. <BR>
</P>
<br><br>
<Table border=0 Width=644 Height=57 cellspacing=0 cellpadding=0 style='font-family:Verdana;font-size:11px;line-height:15px;'><TR><td><a href='http://adworks.rediff.com/cgi-bin/AdWorks/click.cgi/www.rediff.com/signature-home.htm/1050715198@Middle5/1301364_1294999/1300742/1?PARTNER=3&OAS_QUERY=null target=new '><img src =http://imadworks.rediff.com/cgi-bin/AdWorks/adimage.cgi/1301364_1294999/creative_1300742.gif alt='imagine' border=0></a></td></TR></Table>