Skew: Skew methods

Stair, defining the stair’s line of travel and geometry

When you have defined the outline of the stair, you can use the Skew parameter to specify a skew method.

Skew is the term used to describe a staircase where the orientation of the front edge of each step deviates from that of the previous step by a given angle. First, click Angl (for Skew Angle) to determine the angle between the top and bottom steps.

If the angle between the individual steps has been set with Fixed Angle, the difference in the angle and the skew between two consecutive steps (= skew section) is determined. You can use the Skew parameter to select a skew method.

Note: The skew methods provided by Allplan are based on pure mathematics. This helps you find the skew that is best suited to the stair at hand.
The resulting skew is not based on the regulations, rules and minimum dimensions laid down in DIN 18065:2011-06 D. In order to comply with the standard, you may need to adjust the skew proposed by Allplan.

The following skew methods are available:

Skew 1, equal

(A) Skew region

The angle is the same in the entire section.
Each step is skewed by the same angle
relative to the previous step.

Skew 2, linear

(A) Skew region

The relative skew angle between each pair of adjacent steps is
incremented by an even amount at each step.
At the middle of the skewed section,
this process is reversed.

Skew 3, harmonic

(A) Skew region

Harmonic increase in skew angle to the middle of the skewed section
and harmonic decrease as of the middle.

Skew 4, geometrically optimized

The skew is optimized automatically based on
the geometric outline of the stair.
This method is recommended with winders, double
and three quarter-turn stairs.

Skew 5, proportional

Only for u-type stairs.
The proportional skew between two
orthogonal locked stairs is determined.

Skew 6, semi-circle method

Only for u-type stairs.
The skew between two orthogonal locked stairs is determined
using the semi-circle method.