What is Stairs Maker?

Stairs Maker is an add-on for Blender that allows you to create stairs with railings with lots of different customizable options.

When the Add-on is enabled, in the side panel in the 3d Viewport, you'll see the BB Assets Panel. From there, with a simple click on a button, you can transform any selected object into a stairs or a railings object. 

How does this add-on work?

It applies a Geometry nodes modifier to the selected object. These applied node trees create stairs and / or railings objects, but no Geometry nodes experience is needed since all that matters for the user happens inside the side panel of the 3D viewport.
Once the stairs (or railings) are created, this panel populates with lots of options, all organized inside dropdown menus.

Every option is explained in detail in the User Manual that can be downloaded HERE for free.
And you can watch a full tutorial HERE

UPDATES:

1.1.1. (Blender 3.3, 3.4)
first version

1.1.3. (Blender 3.3, 3.4)
adjust vertical bars Z size is now possible even with no horizontal bars
fiixed alignment bug with vertical bars

1.2.2. (Blender 3.5)
When applying geometry a real UVmap gets created (see manual) that can be used when exporting this geometry into other software.

1.2.3 (Blender 3.5)
Fixed Bug with inverted normals when applying geometry when reverse path curve is enabled

1.3.1 (Blender 3.6)
Updated for Blender 3.6
From this version, there is no longer the need to keep the geonodes modifier active

1.4.1 (Blender 4.0)
Updated for Blender 4.0

2.1.1 (Blender 4.2)
Updated for Blender 4.2

2.2.1 (Blender 4.2)
Renamed panel from "BB Assets" to "Stairs Maker"
Small bug fix

2.2.2 (Blender 4.2)
Fixed bug with multiple Railings Objects

3.4.4 Updated for Blender 4.4
Gizmo Editing – Introduced 32 interactive gizmos, allowing you to adjust the staircase directly in the 3D Viewport with intuitive visual controls.
Presets System – Added 6 default presets and support for up to 8 custom presets, letting you save and reload your favorite staircase and railing styles.
Tapered Staircases – New Taper parameter lets you control the width variation from bottom to top of the staircase.
Post Z Rotation Randomization – Added a parameter to apply randomized Z-axis rotation to each post.
Handrail Swirl – You can now twist (swirl) the handrail along its path for a dynamic look.
Handrail Z Offset (Random & Zig Zag) – Added parameters for vertical variation of handrail profiles using random or zig zag patterns.
Vertical Bar Z Rotation Randomization – Each vertical bar can now have a random Z-axis rotation for a more organic appearance.
Vertical Bar Z Offset (Random & Zig Zag) – New controls allow vertical bars to move up or down along the Z-axis, with random or zig zag variations.
Horizontal Bar Swirl – Horizontal bars can now be twisted (swirled) along their length.
Horizontal Bar Z Offset (Random & Zig Zag) – Same as for handrails: random or zig zag vertical movement is now supported.
Extend Horizontal Bar Start/End – You can now extend the start and/or end of the horizontal bars, similar to how it already worked for handrails.
Independent Vertical Bar Height – A new parameter lets you adjust the Z size (height) of vertical bars independently of the number of horizontal bars.

3.5.1 Updated for Blender 4.4.
Added a parameter to adjust beam spacing – You can now control the distance between
supporting beams in the staircase construction for better structural flexibility and visual customization.
Added a whole new sections - Stringers

3.5.2 Updated for Blender 4.4.
Fixed a bug with smooth shading of the handrail