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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>This seems like it should be an easy thing to do, but none of the documentation or examples I’ve seen seem to do what I want. I would like to draw 3D geometry on top of a 2D background image. I want the image to subtend a fixed angular extent, e.g. if the camera FOV is 30deg, and I define the image as 30deg, I want it to fill the vertical extent of the render window (assuming the camera is not set to Use Horizontal View Angle) . I want *<b>all</b>* 3D geometry also in the scene to be drawn on top of the image – i.e. the image shouldn’t have a “position” which would allow it to obscure the 3D geometry. When I change the camera pose, I want to provide a new image, but I don’t want the image to be viewed at an oblique angle – I want it to be centered facing the camera again. vtkImageActor just maps an image onto a planar surface sitting out in space and doesn’t maintain its place and orientation in the render window. Basically, I want the functionality of vtkFollower, but in addition to automatically correcting its orientation so that it always faces the camera, I want it to automatically correct its position so that it’s always in the center of the field of view and always at the right distance. Does this functionality exist anywhere or do I need to jump through some hoops in my render loop to achieve this? <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:24.0pt;font-family:"Monotype Corsiva"'>Chris</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Times New Roman","serif"'>--<br>Christopher R. Volpe, Ph.D. </span><span lang=FR style='font-size:10.0pt;font-family:"Times New Roman","serif"'>Email: <a href="mailto:cvolpe@ara.com">cvolpe@ara.com</a> <o:p></o:p></span></p><p class=MsoNormal><span lang=FR style='font-size:10.0pt;font-family:"Times New Roman","serif"'>Senior Scientist, Information Exploitation Systems Main Desk: 919-582-3300<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Times New Roman","serif"'><a href="http://www.ara.com/">Applied Research Associates, Inc</a> Direct: 919-582-3380<o:p></o:p></span></p><p class=MsoNormal><span lang=FR style='font-size:10.0pt;font-family:"Times New Roman","serif"'>8537 Six Forks Rd., Suite 6000 Fax : 919-582-3301<o:p></o:p></span></p><p class=MsoNormal><span lang=FR style='font-size:10.0pt;font-family:"Times New Roman","serif"'>Raleigh, NC 27615 Web: </span><span style='font-size:10.0pt;font-family:"Times New Roman","serif"'><a href="http://www.ara.com/offices/NC.htm" title="http://www.ara.com/offices/NC.htm">http://www.ara.com/offices/NC.htm</a></span><span lang=FR style='font-size:10.0pt;font-family:"Times New Roman","serif"'><o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <span style='font-size:12.0pt'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>