Three-dimensional objects are produced from a deformable material received substantially continuously in the direction of production and the objects are produced by a deforming process substantially in the direction of production. Rotatable devices are arranged to deform a respective section of the deformable material with at least one of the rotatable devices being shaped so as to vary the extent of deformation applied to the deformable material periodically as a deformable material passes through in the direction of production.