a three - dimensional complex preform is made formed of various types of reinforcement fiberglass fibers with a binder at the interstices which rigidize the preform to the shape and form approximating the molded article , which can be handled and stored until a final mold is made filling the interstices with plastic and curing the plastic . complex preforms require either specific reinforcements in the form of increased sections , specific reinforcement , or require modification or enlargement in size or increase in complexity by the attachment of one or more additional preforms . to modify an existing preform and obtain a desired shape and form , reinforcement members or additional preforms are attached by energetic stitching . energetic stitching includes the application of an electromagnetic energy curable binder and the application of electromagnetic radiation to cure the binder . the stitching normally occurs over a restricted area defined by the contact surfaces to join two or more members and the restricted area is obtained in various forms such as by applying binders in preselect areas , or by applying the curing radiation in preselect areas or by masking the application of the binder or masking the application of the energy by controlling of the location and / or areas where the stitching is applied . substantial modifications and flexibility in the type of resultant preform can be attained whether the preform has an add on reinforcement member or is formed by the attachment of one or more additional preforms to it to obtain a complex resultant preform .