Patent ID: 7879282

Claim:
A method of selectively sintering particulate material, comprising the steps of: (i) providing a layer of particulate material; (ii) providing radiation over the layer of particulate material; (iii) varying the absorption of the provided radiation across a selected surface portion of the layer to sinter a portion of the material of the layer; (iv) providing a further layer of particulate material overlying a prior layer of particulate material including a previously sintered portion of material; (v) repeating steps (ii) and (iii) to sinter a further portion of the material within the overlying further layer and to sinter said further portion with the previously sintered portion of material in the prior layer; (vi) successively repeating steps (iv) and (v) to form a three-dimensional object; wherein step (iii) comprises varying the radiation absorption at the particulate material over the selected surface portion of the layer by providing an amount of radiation absorbent material over the selected surface portion of the layer.