I am attempting to route some pipework in Solidworks 2015. I have placed two flanges and selected the system to 'Auto Route' between them which it does. However when I exit the sub-assembly I get an error message saying 'the pipe must have a length@extrusion dimension'. It then proceeds to reduce all the pipe lengths to the same size, but leaves the flanges and elbows where they are so the pipework is no longer connected. Doe anyone know how to fix this problem?