Below is a great little CADclip on how to create a roof cricket around a roof pentration.
In the CADclip above we use the normal roof edge slope methods and 2 very small edges.
You can also accomplish this cricket by using two 'Slope Arrows' as shown in the image below.
In the image below I placed the 2 slope arrows along the gable end of the cricket pointing towards the middle of the cricket. Note that you do NOT need to split the roof footprint linework on the gable edge. The roof footprint is made up of 3 segments only. Then to set the slope properties select the slope arrow(s) and use the properties palette. You can modify both arrows at the same time.