SH3DImporter: Fix walls Length attribute (#18854)

* Make IFC project optional

* make sure wall.Length is properly set

---------

Co-authored-by: Yorik van Havre <yorik@uncreated.net>

src/Mod/BIM/Resources/ui/preferences-sh3d-import.ui

@@ -261,7 +261,7 @@
             <item>
               <widget class="Gui::PrefCheckBox" name="checkBox_10">
                 <property name="toolTip">
-                  <string>Create a default Render project with the newly Site</string>
+                  <string>Create a default Render project with the newly created Site</string>
                 </property>
                 <property name="text">
                   <string>Create Render Project (requires Render)</string>
@@ -350,4 +350,4 @@
   </customwidgets>
   <resources />
   <connections />
-</ui>
+</ui>

src/Mod/BIM/importers/importSH3DHelper.py

@@ -848,6 +848,9 @@ class WallHandler(BaseHandler):
             wall = Arch.makeWall(solid)
         else:
             wall = Arch.makeWall(sweep)
+        # For some reason the Length of the spine is not propagated to the
+        # wall itself...
+        wall.Length = spine.Length
         return wall
 
     def _get_wall_details(self, floor, elm):