A method of precision assembly of component parts of an article uses a laser light projection system in combination with a photoreactive material. The photoreactive material is applied to the component parts of the article being assembled, where the photoreactive material is exposed to the laser light emitted by the projector system. When the photoreactive material is exposed to the laser light, the appearance of the material changes to mark a location on the material and thereby on the component part where an assembly operation is to take place.