@Ceciliabr

The faces have been flipped. I have flipped them back, and the clock renders fine with both Sunflow and YafaRay.

How did you flip the faces in the right direction?


@Puybaret

There must be a problem with double sides or with normals in the Mantle Clock.

By removing the normals, I also get a correct rendering with YafaRay.
Does this mean that YafaRay and SunFlow do not handle misdirected faces in the same way?