I am currently rendering a character who has fur for hair. I am using mental ray and for a time the fur was rendering perfectly. Recently the fur stopped rendering on my computer informing me that the fur feedback shape is not a valid suface and is ignored and also that no visible fur is found. I tried to render on my friend's computer and the fur rendered in exactly the same scene and render global set up as the one which failed on mine. However now the fur has also failed on my friend's computer. Can anyone think of a reason/solution for this seemingly random problem?