No there is no displacement I have remodeled and the problem has gone. seachnasaigh posted at 5:41PM Mon, 22 February 2016 - #4256765

Does the roof shake/shingle material use displacement? If so, what is your min displacement bound in the Firefly render settings? Show an advanced material room screen grab of the shake/shingle material, with all nodes fully opened (both the data section and the preview window).

I question whether the texture image is fitted to the UV mapping, given the black strip near the peak (one side only) and since the edge is above the roof when viewed from the back.

MacBook Pro OSX El Capitan Ver 10.11.6