Shear and torsion design or check is performed at each section for maximum shear force along the maximum torsion. This is calculated at the immediate left and right side of every section except at the beginning and end of span. Only the section to the right of the beginning of span is evaluated; only the section to the left of the end of span is evaluated. In Auto Design, program tries to come up with stirrup spacing that satisfies the required transverse reinforcement Av/s (total transverse reinforcement area per unit length). In addition to Av/s, program also considers the maximum spacing allowed as per clause 304.7.1.6, IRC 21-2000, which is smaller of 0.5*depth of beam or 300 mm .