Abstract: A method of forming a three dimensional fiber structure is disclosed which comprises the steps of a) providing a starting material which comprises liquid carrier, fibers and binder; b) passing the starting material over a substrate so as to deposit fibers onto the substrate; c) forming a three dimensional fiber matrix; and d) curing the binder. The flow of material onto the substrate may be controlled such that the flow of a starting material over the substrate is chaotic and fibers are laid down in a three dimensional structure containing a high proportion of voids. The preform may be pressurized while moist and is cured under pressure. The fibers may comprise carbon fibers; recycled carbon fiber has been found to be particularly useful. The resulting preform may be stochastic and is suitable for use in ablative and braking applications.