On the Calculation Parameters tab you define basic values for calculations for a slab (the French RC code BAEL parameters are adopted). 
- Parameters of concrete (concrete class, strength, unit weight). 
 
- Parameters of reinforcing steel (steel grade, strength). 
 
- Direction of main reinforcement (along the X / Y axes). 
 
- Diameter of main and perpendicular reinforcement (top and bottom). 
 
- Reinforcement cover (top and bottom). 
 
- Environment class. 
 
- Value of the allowable deflection.