Hi, Define a box made of your plate material. The a daughter which is a cylinder made of air. Incline this cylinder to get the position you need. The daughter cylinder will escape a bit from its mother volume, but as soon as the particles are coming from outside those volumes, it will works fine. Cheers, Simon <div class="gmail_quote">On Wed, Mar 6, 2013 at 4:40 PM, Cui, Yonggang <<a href="mailto:ycui@bnl.gov" target="_blank">ycui@bnl.gov</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div link="blue" vlink="purple" lang="EN-US"> <div> Thanks, Marc. What I am looking for is the shape shown below (I hope my sketch is clear): <img src="cid:image003.jpg@01CE1A57.07CA2BD0" height="235" width="400"> Thanks, Yonggang From: Vesna Cuplov [mailto:<a href="mailto:vesna.cuplov@gmail.com" target="_blank">vesna.cuplov@gmail.com</a>] Sent: Wednesday, March 06, 2013 9:38 AM To: Marc Chamberland Cc: Cui, Yonggang; <a href="mailto:gate-users@lists.opengatecollaboration.org" target="_blank">gate-users@lists.opengatecollaboration.org</a><div class="im"> Subject: Re: [Gate-users] How to create this - slant hole in a plate</div> Hello,<div><div class="h5"> I am not totally sure about the geometry you want to create for the hole but I added the following volume in Gate v6.2 which is an Elliptical Tube. You might try it and see if it suites your needs. See the User's guide: <a href="http://wiki.opengatecollaboration.org/index.php/Users_Guide_V6.2:Defining_a_geometry" target="_blank">http://wiki.opengatecollaboration.org/index.php/Users_Guide_V6.2:Defining_a_geometry</a> and <a href="http://geant4.web.cern.ch/geant4/G4UsersDocuments/UsersGuides/ForApplicationDeveloper/html/Detector/geomSolids.html" target="_blank">http://geant4.web.cern.ch/geant4/G4UsersDocuments/UsersGuides/ForApplicationDeveloper/html/Detector/geomSolids.html</a> (G4EllipticalTube) and <a href="http://mathworld.wolfram.com/CylindricalSegment.html" target="_blank">http://mathworld.wolfram.com/CylindricalSegment.html</a> Don't know if it will help. vesna </div></div><div><div class="h5"> <div> On Wed, Mar 6, 2013 at 2:11 PM, Marc Chamberland <<a href="mailto:MarcChamberland@cmail.carleton.ca" target="_blank">MarcChamberland@cmail.carleton.ca</a>> wrote: <div> As far as I know, this is not possible with the current geometry features of Gate. <div> </div> <div> However, since Gate is open source, you can add the feature yourself! </div> <div> </div> <div> If you look at the source code, you'll see that the volumes that Gate supports are Geant4 volumes. A look at the Geant4 source code reveals that it supports many more volumes than Gate. There might be one or more volumes that suit your need in there. You just need to implement it in Gate (using the current source code as a template). It should be relatively straight forward... but your geometry need is a bit complex... </div> <div> </div> <div> Good luck! <div> <div> <div> Marc </div> <div> </div> </div> </div> </div> </div> </div> </div></div></div> </div> _______________________________________________ Gate-users mailing list <a href="mailto:Gate-users@lists.opengatecollaboration.org">Gate-users@lists.opengatecollaboration.org</a> <a href="http://lists.opengatecollaboration.org/mailman/listinfo/gate-users" target="_blank">http://lists.opengatecollaboration.org/mailman/listinfo/gate-users</a> </blockquote></div>