Hi Edoardo, The translation applied on your rsector in point 2) (either following the X or Y axis) will affect the way to describe your array repeaters in point 5) (this which repeats your first created crystal). So if you really just changed point 2), the problem could be easily explained. Have you watched your scanner with OpenGl or something to see if you obtained what you expected ? However for your negative radius, I have no idea ! Cheers, Simon <div class="gmail_quote">On Fri, Jan 30, 2009 at 2:52 PM, Edoardo Pasca <<a href="mailto:e.pasca@nki.nl">e.pasca@nki.nl</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="Ih2E3d">On Thu, 2009-01-29 at 15:40 +0100, Edoardo Pasca wrote: > Hi all, > > I am running a slightly modified version of the full_simulation example, > and I get a whole bunch of this messages: > > C is too big to make the ID : C = 61 Max < 29 </div>Even though I didn't exactly figured out what this message means, I figured out what it is about: 29 is the number of crystal along the Z direction of the detector. Now, that message is saying something like "the event happened outside the crystal". Anyhow, I checked how I designed the detector of type cylindricalPET: 1) create rsector 2) move it to 0 N 0 mm 3) create crystals 4) create layer 5) apply the repeater 6) attach the pieces This is different, on the point 2, from what always described on the manual: during design, on the manual, the shift goes on the X direction, rather than on the Y. As a matter of facts I also noticed that the output of  /gate/systems/cylindricalPET/describe gave me a negative radius of the scanner, which was highly suspicious. I just changed point 2 and shifted the rsector to N 0 0 mm and now the simulation goes fine. I guess that this is somehow a bug, because there shouldn't be dependence on that kind of shift. My best Edoardo <div class="Ih2E3d"> > > I checked the original example does not show that message. What did I do > wrong? What is C? > > Thanks for any help > > Edoardo </div><div><div></div><div class="Wj3C7c">_______________________________________________ Gate-users mailing list <a href="mailto:Gate-users@lists.healthgrid.org">Gate-users@lists.healthgrid.org</a> <a href="http://lists.healthgrid.org/mailman/listinfo/gate-users" target="_blank">http://lists.healthgrid.org/mailman/listinfo/gate-users</a> </div></div></blockquote></div>