https://forums.autodesk.com/t5/autocad-forum/find-point-where-line-intersects-3dface/m-p/12168367#M30890 <P>you have asked a similar question in another post. You can do a similar thing here. If the line does not cross the face, extend the face to find the breakpoint and cleanup afterwards.<BR /><BR /><A href="https://forums.autodesk.com/t5/autocad-forum/trim-lines-to-3dface/td-p/12168276" target="_blank">https://forums.autodesk.com/t5/autocad-forum/trim-lines-to-3dface/td-p/12168276</A></P> Sun, 13 Aug 2023 22:39:26 GMT Michiel.Valcke 2023-08-13T22:39:26Z https://forums.autodesk.com/t5/autocad-forum/find-point-where-line-intersects-3dface/m-p/12168340#M30889 <P>Is there a way to trim this ridge line (in red) to the roof plane in order to resume drawing the valleys that are created here?</P><P>&nbsp;</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="2023-08-13 15_10_23-Autodesk AutoCAD 2015 - [20 El Prado [roof model].dwg].png" style="width: 600px;"><img src="https://forums.autodesk.com/t5/image/serverpage/image-id/1252748iAFE1150F1B6DF01B/image-size/medium?v=v2&amp;px=400" role="button" title="2023-08-13 15_10_23-Autodesk AutoCAD 2015 - [20 El Prado [roof model].dwg].png" alt="2023-08-13 15_10_23-Autodesk AutoCAD 2015 - [20 El Prado [roof model].dwg].png" /></span></P><P> </P> Sun, 13 Aug 2023 22:11:12 GMT https://forums.autodesk.com/t5/autocad-forum/find-point-where-line-intersects-3dface/m-p/12168340#M30889 jdfnnl 2023-08-13T22:11:12Z https://forums.autodesk.com/t5/autocad-forum/find-point-where-line-intersects-3dface/m-p/12168367#M30890 <P>you have asked a similar question in another post. You can do a similar thing here. If the line does not cross the face, extend the face to find the breakpoint and cleanup afterwards.<BR /><BR /><A href="https://forums.autodesk.com/t5/autocad-forum/trim-lines-to-3dface/td-p/12168276" target="_blank">https://forums.autodesk.com/t5/autocad-forum/trim-lines-to-3dface/td-p/12168276</A></P> Sun, 13 Aug 2023 22:39:26 GMT https://forums.autodesk.com/t5/autocad-forum/find-point-where-line-intersects-3dface/m-p/12168367#M30890 Michiel.Valcke 2023-08-13T22:39:26Z https://forums.autodesk.com/t5/autocad-forum/find-point-where-line-intersects-3dface/m-p/12169479#M30891 <P>Search is your friend.&nbsp; There's an extensive topic on this very question, <A href="https://forums.autodesk.com/t5/visual-lisp-autolisp-and-general/to-get-intersection-between-a-line-and-a-3dface/m-p/2745633" target="_blank" rel="noopener">&gt;here&lt;</A>.</P> Mon, 14 Aug 2023 12:16:43 GMT https://forums.autodesk.com/t5/autocad-forum/find-point-where-line-intersects-3dface/m-p/12169479#M30891 Kent1Cooper 2023-08-14T12:16:43Z