Hi, your post is still flagged as "This post has NOT been accepted by the mailing list yet. " so noone gets it on the mailing list. Check your registration as per this. <http://forum.openscad.org/mailing_list/MailingListOptions.jtp?forum=1> Re your question. Imported STLs are 3D objects, so difference() should work on them just like on a cube(). If not it probably means the STL is not manifold or is otherwise stuffed. Get a copy of Netfabb basic <http://www.netfabb.com/downloadcenter.php?basic=1> to check your STL, or post a link to it and I can check it. ----- Unless specifically shown otherwise above, my contribution is in the Public Domain; To the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. This work is published globally via the internet. :) Inclusion of works of previous authors is not included in the above. The TPP is no simple “trade agreement.” Fight it! http://www.ourfairdeal.org/ -- View this message in context: http://forum.openscad.org/Difference-from-imported-STL-tp13135p13401.html Sent from the OpenSCAD mailing list archive at Nabble.com.