The main window is divided into two parts: The left-hand side is used for reciprocal-space visualisations: The tab "Reciprocal Lattice" shows the Bragg peaks in the current scattering plane and the scattering triangle, the tab "Projection" shows various projective views, e.g. for calculating Laue patterns. The right-hand side of the window depicts several real-space visualisations: Here, the real lattice and the crystal's unit cell are shown (tab "Real Lattice") as well as the current instrumental position for triple-axis spectrometers (tab "TAS Instrument") and for time-of-flight spectrometers (tab "TOF Instrument").
The lattice constants and angles of the crystal's unit cell are entered in the lower-left part of the Takin main window using either the "Real Lattice" or the "Recip. Lattice" tab. The tab "Recip. Plane" defines the scattering plane used by the spectrometer.
If a space group is defined (lower-central part of the main window), the forbidden reflexes are excluded in the reciprocal-lattice view. Furthermore, the structure factor and the crystal's unit cell are displayed if the atom positions are known: they can be entered using the "Atoms..." button.