strange black lines on object when rendered ive encountered a similar problem to a lot of other people i saw in forums but none of them were the same as mine.

the object was made using a cube with a path and array modifier to create the curved shape. the problem persists whether or not the modifiers have been applied. there are no materials and even when i do add a material the lines are still present. the lines don't seem to change shape or position when the camera is moved around. i have tried removing doubles and recalculating normals but it hasn't helped.







any help much appreciated
I have not seen this behaviour before but if you select the arch and Set Origin to geometry the artefacts will go away. I suspect that it's related to precision errors when the geometry is too far away from the origin.