The program calculates automatically within certain tolerances, using the step dimensions of the stairs, a reasonable relationship between rise and tread depth (note: gradient/ = two steps + one tread; the ideal gradient based on the length a person’s step is 63 cm). If for example, you change the length of the run of the stairs and then switch to another input field, the ‘Modify run length’ dialog appears. Here you have the choice of three options as to how the stairs should be adapted to suit the new length.
In this case the number of steps remains constant and the tread depth is changed. If the tread depth is increased, then the length of the run of the stairs changes. If you change the number of steps, the length of the run changes but the tread remains the same. The value ‘Height of starting step’ allows you to set the height of the stairs above the finished floor. If you uncheck the box ‘automatic positioning above construction’, then the height of the staircase can be adjusted to suit your specific requirements. In this case only the unit rise of the staircase changes.
Changes to the measurements of the staircase and the steps are so designed that you can specify the settings for the staircase to meet your specific requirements, without being hindered by automatic functions. Therefore, you have to be aware yourself, as to what extent the gradient adheres to the rule for the length of a person’s step.