Shape setting is currently a well procedure used by engineers to form a NiTi component into shape desired for a particular application.  When starting from cold worked  material, the shape setting is conventionally performed by exposing the NiTi elements fixed in various fixtures to high temperatures ~500 °C for several minutes. Following such heat treatment under constraint, not only that the austenite shape is memorized but the functional properties are set as required.  Although everything seems to be very easy and safe, it is not always the case. There are many problems encountered in practice - cold worked elements are just elastic and difficult to insert into some fixtures, the elements break in fixtures, functional properties of treated elements are not exactly those as required, if one starts from fully or partially treated elements, the standard shape setting procedure does not lead to shape setting, the austenite shape, though achieved, is not stable in just a few mechanical cycles etc.  In order to understand the origin of these problems it is beneficial to know details about the physical processes taking place in NiTi components during the shape setting (at high temperatures and stresses). We have performed series of experiments on thin superelastic NiTi wires heat treated by non-conventional FTMT-EC (Final thermomechanical treatment by electric current) under applied tensile stress. TEM, in-situ X-ray and electrical resistivity measurements were used to track the activity of the physical processes responsible for the shape setting. These aprocesses are triggered in the microstructure exposed to high temperatures and stresses. It is found that the shape setting is related to the onset of dynamic recrystalization and/or plastic deformation in the martensite state. The FTMT-EC method makes it possible to shape set the NiTi components in just few miliseconds eliminating effectively the diffusion processes in a matrix.