Category Archives: Stair Settings

Custom Shaped Stairs

Have you been faced with a stair shape too daunting to model? Arching, balanced, curved, or spiral stairs can be difficult and may seem like there is no tool out of the box to do what you need. Morphs are great, but when shapes get complicated morphs do not always cooperate the way you would expect them to.

Now along comes the stair tool! The stair tool has many default shapes for “L”, “U”, Spiral or Straight runs of steps. Each has a huge range of graphic and geometric settings all in a user friendly interface to help you essentially script a GDL based object.

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But if you stair is more complicated than the shape options provided by the stair tool, you will want to use a custom stair. To define a custom stair you only need two drafted elements; a fill with at least two non-curved edges to define the perimeter of the stair and a series of lines or arcs all connected to define the walk line (center or average of stair width).

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With these 2d elements selected go to design > create stair using selection.

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The resulting dialog box is identical to the standard “Stair Type Selection”, but the only option available will be a custom stair shape.

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After this you will go through the standard stair editing options to set tread and riser dimensions, nosing overhangs, base and top connections, fills and pen weights as well as plan symbol options.

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I strongly recommend leaving the integrated guard rail off for most stairs. The options are almost never what we want to see, even as a schematic design model. Most guard rails can be designed and modeled relatively quickly with the beam, column and morph tools.


If you need to turn a background fill on your stairs, or match the fill above the break line to a background fill below the break line, the setting is in the attributes section of the stair editor. If you do not have “show fill above break line” checked, you may still have a fill in your plan view, depending on MVO and renovation overrides. To get the fill above the breakline to match the fill below the breakline, ensure this box is checked and apply a fill that works for both locations, or transparent background for stairs that do not mask.

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