Unknown lines in preview

[Lunatic728 0]

So I am at a loss to find out what these lines are.  They only appear in this model and I just can't seem to find an answer.  

 

The Blue / Purple lines just above the support lines.   

 

[GregValiant 1,330]

It's under Support | Enable Support Interface.  What you have there is the Roof interface enabled.  It looks to be 1mm thick and is likely set to Grid.

I usually allow a space of 1 layer between the top of the interface and the first real layer above so they don't bond together so well.  That setting is Support Z Distance.  Another important one is the density of the interface.  I run that from 25% to 60% dependent on the model.  If the interface is too dense there will be millions of retractions.  If it is too sparse for the model the first real layer can sag between the lines of the interface.

[Lunatic728 0]

Thank you it was driving me nuts.   Got it all fixed now.