https://community.graphisoft.com/t5/Modeling/Help-trimming-walls-to-roof/m-p/207281#M112279 how are you trimming the walls? using the Wall Trimming option is quicker but not as efficient as using solid element operations(SEO's) IMO. select all yuor walls that have been trimmed, open wall settings, cancel the trim operation, open SEO dialogue, with walls selected, hit Get Target Elements. Then deslect the walls, select your roof/s and click Get Operators in the SEO dialogue. Choose the 'extrude upwards' option and apply! Tue, 06 Nov 2012 13:38:54 GMT Anonymous 2012-11-06T13:38:54Z https://community.graphisoft.com/t5/Modeling/Help-trimming-walls-to-roof/m-p/207280#M112278 <DIV class="actalk-migrated-content"><T>Hi - someone please help me!!<BR /> <BR /> I've been trying to trim walls to the roof of this building, but bits of the walls keep disappearing or the wall gets holes in it or disappears completely!<BR /> <BR /> Any suggestions?<BR /> <BR /> Thanks very much for any help you could offer!</T></DIV><BR /><IMG src="http://community.graphisoft.com/t5/image/serverpage/image-id/70814i9500961E70C9CFDD/image-size/large?v=v2&amp;px=999" border="0" alt="Archicad.jpg" title="Archicad.jpg" /> Tue, 23 May 2023 12:39:19 GMT https://community.graphisoft.com/t5/Modeling/Help-trimming-walls-to-roof/m-p/207280#M112278 Anonymous 2023-05-23T12:39:19Z https://community.graphisoft.com/t5/Modeling/Help-trimming-walls-to-roof/m-p/207281#M112279 how are you trimming the walls? using the Wall Trimming option is quicker but not as efficient as using solid element operations(SEO's) IMO. select all yuor walls that have been trimmed, open wall settings, cancel the trim operation, open SEO dialogue, with walls selected, hit Get Target Elements. Then deslect the walls, select your roof/s and click Get Operators in the SEO dialogue. Choose the 'extrude upwards' option and apply! Tue, 06 Nov 2012 13:38:54 GMT https://community.graphisoft.com/t5/Modeling/Help-trimming-walls-to-roof/m-p/207281#M112279 Anonymous 2012-11-06T13:38:54Z