The Head Clearance or Ceiling values are bad or out of range.
The Head Clearance value must be greater than or equal to zero.
The Fit Height, Riser Min or Riser Max values are bad or out of range.
The Riser Min and Riser Max values must be greater than zero.
The Riser Max value must be greater than or equal to the Riser Min value.
Using these values, the number of treads for the staircase is less than or equal to zero. It might be impossible to fit a whole number of treads using this range of riser values.
The Riser value is bad or out of range.
The Riser value must be greater than zero.
The Stair Width value is bad or out of range.
The Stair Width value must be greater than zero.
The Start Z value is bad or out of range.
The Start Z value must be greater than or equal to zero.
The Tread value is bad or out of range.
The Tread value must be greater than zero.
The Tread Thickness value is bad or out of range.
The Tread Thickness value must be greater than zero and less than the (min) riser height.
The Stringer Thickness value is bad or out of range.
The Stringer Thickness value must be greater than zero and less than or equal to half the Stair Width value.
The Fit Height for ascending staircases must be greater than the Start Z value.
The Fit Height for descending staircases must be less than the Start Z value.