Predictive Design Technology – Stairs

Staircases have traditionally been a headache for architects. Complicated structures, tight spaces and stringent standards make designing stairs one of the most complicated tasks in architecture. Archicad’s predictive design stair tool simplifies the whole stair design process.

Designers choose from multiple design options while Archicad ensures the stairs comply with local and global standards. The stair’s shape can easily be tweaked, along with customised structural elements and finish components.

An overview of stair design

Stair design and construction is restricted by a set of regulations that vary from country to country, including rules on risers, treads, landings, and stair pitch. These local standards strive for the same goal; to design a stair that is safe and comfortable to walk on, while creating an aesthetically pleasing support for the structure.

With conventional pen-and-paper architectural design, 2D CAD design, and even contemporary BIM solutions, designers must manually ensure that these rules are adhered to, which is a laborious and time-consuming process.

Our solution helps architects to quickly and easily design stairs that meet the local regulations. Architects can create, design and efficiently document any typical or unique stair, at any scale.

Introducing Predictive Design Technology©

Stair Solver

Archicad’s Predictive Design Technology© provides a next-generation stair tool, simplifying and accelerating the stair design process using sophisticated algorithms to ensure that the stair meets the required regulations and is both safe and constructible.

The stair tool takes its input from three sources:

  1. Local standards.
  2. Project context, including storeys, adjacent walls, and stair type.
  3. Design intent, as prescribed during placement.

Based on these, Archicad will either offer a single specific stair design, or will offer a selection of the best options to choose from.

If the specific stair design can be accomplished, it will be shown as a live preview while moving the mouse. If the exact stair design cannot be achieved within the given input parameters, Archicad runs an analysis of several thousand possible parameter combinations for compliant stair designs in the background and offers a selection of the best options to choose from. The preferred alternative design can instantly be selected, providing a well-informed one-click resolution.

How Predictive Design Technology© simplifies stair design

Archicad’s solution aims to help design stairs that meet the required local regulations, quickly and easily. To do this, Archicad uses three main components:

  1. A set of customisable construction rules, providing the constraints and describing the local regulations. The values for the rules can be preset according to the localized version or project template, and can be customised on the on the fly for individual stairs or construction types.
  2. An automatic stair construction algorithm, based on various information provided by the designer, and is specific to the projest. This includes the total stair height, number of steps, stair width, walking line, turning types, and a polyline “baseline” of the stair. Based on these inputs and the set of rules, Archicad automatically constructs a stair.
  3. A graphical interface with automatic solutions to resolve conflicts. In some cases, the input values and the polyline path provided by the user cannot result in an adequate stair. If this is the case, there are certain geometric modifications that could create a stair by following the set rules.

When it is not possible to construct a stair that follows all the given rules, the algorithm generates another modified stair in the background using the last strategy in its self-learning solutions list. If the process produces a valid stair, the algorithm generates possible solutions to choose from, highlighting what changes have been made. Selecting any of the possible solutions will instantly give graphical feedback showing how the modified stair would look in context.

Stair design


With the help of predictive design in Archicad, architects can design stairs quickly and easily, ensuring that they meet the required local regulations every time.

Graphisoft’s Predictive Design Technology© helps to reduce time in creating and checking stair designs, improving efficiency throughout the design process, therefore reducing costs and improving project profitability.

In future, Graphisoft plans to apply Predictive Design Technology© to other design elements within Archicad to help eliminate further manual, time consuming tasks.