https://community.graphisoft.com/t5/Modeling/Trimming-walls-to-the-roof-how-to-get-rid-of-the-outlines/m-p/278664#M144468 Malgorzata Anton:<BR /> <BR /> Another option: use Solid Element Operation: Subtraction with upward extrusion rather than Connect: Trim Elements to Roof/Shell if you don't want to change the Building Material Intersection Priority.<BR /> <BR /> David Wed, 24 Jun 2015 12:34:37 GMT David Maudlin 2015-06-24T12:34:37Z https://community.graphisoft.com/t5/Modeling/Trimming-walls-to-the-roof-how-to-get-rid-of-the-outlines/m-p/278662#M144466 <DIV class="actalk-migrated-content"><T>Hi!<BR /> <BR /> I'm modelling a house in ArchiCAD and when I trim the walls I get a weird outcome, the lines of the walls are visible on the other side of the roof. <BR /> How can I change it?<BR /> <BR /> Thanks for your help,<BR /> M.</T></DIV><BR /><IMG src="http://community.graphisoft.com/t5/image/serverpage/image-id/72977i8203D9CBA0D55D4E/image-size/large?v=v2&amp;px=999" border="0" alt="Capture.JPG" title="Capture.JPG" /> Tue, 23 May 2023 12:26:11 GMT https://community.graphisoft.com/t5/Modeling/Trimming-walls-to-the-roof-how-to-get-rid-of-the-outlines/m-p/278662#M144466 Anonymous 2023-05-23T12:26:11Z https://community.graphisoft.com/t5/Modeling/Trimming-walls-to-the-roof-how-to-get-rid-of-the-outlines/m-p/278663#M144467 You will probably find that the Building Material strength for the roof is weaker than that for the wall.<BR /> Make the roof BM stronger and all should be good.<BR /> <BR /> Barry. Wed, 24 Jun 2015 07:00:05 GMT https://community.graphisoft.com/t5/Modeling/Trimming-walls-to-the-roof-how-to-get-rid-of-the-outlines/m-p/278663#M144467 Barry Kelly 2015-06-24T07:00:05Z https://community.graphisoft.com/t5/Modeling/Trimming-walls-to-the-roof-how-to-get-rid-of-the-outlines/m-p/278664#M144468 Malgorzata Anton:<BR /> <BR /> Another option: use Solid Element Operation: Subtraction with upward extrusion rather than Connect: Trim Elements to Roof/Shell if you don't want to change the Building Material Intersection Priority.<BR /> <BR /> David Wed, 24 Jun 2015 12:34:37 GMT https://community.graphisoft.com/t5/Modeling/Trimming-walls-to-the-roof-how-to-get-rid-of-the-outlines/m-p/278664#M144468 David Maudlin 2015-06-24T12:34:37Z https://community.graphisoft.com/t5/Modeling/Trimming-walls-to-the-roof-how-to-get-rid-of-the-outlines/m-p/278665#M144469 Thank you, it worked:) Wed, 24 Jun 2015 23:35:09 GMT https://community.graphisoft.com/t5/Modeling/Trimming-walls-to-the-roof-how-to-get-rid-of-the-outlines/m-p/278665#M144469 Anonymous 2015-06-24T23:35:09Z