I am using the smallest part available (15 x 15 Rect Structure 24 dia Frm 4 FmHt 2 Slab 3 Wall 4 Floor) without creating anything new. It appears that what I will call a wipeout, for a manhole makes the pipes look like they don't connect. The label does list all inverts, but it appears to end 2'-3' away from the structure. Where might this setting be?