There is provided a method of forming a structure that is in contact with an object, the method comprising: (i) supporting a flowable precursor with a flowable support at a position that allows said flowable precursor to be in contact with the object; and (ii) crosslinking at least part of the flowable precursor that is in contact with the object to form a structure that is in contact with the object, wherein a top surface of the part of the flowable precursor that is to be crosslinked, is in interface with a fluid medium. Also provided is a system for performing the method.