The usual question will be: What are the differences between an ATIS 3 and an ATIS 4? The best shortcut to answer this question is to reverse it and describe what remained similar. That is to say, the shape, aspect ratio, numbers of cells and
diagonal strutures, all other parameters and elements have been changed. Symmetrical profile, shortened lines, vault more open, gradual reduction of the width of the panels…put that all together with new materials used and what you get is ATIS 4!