How to Use the Stair Tool in BricsCAD BIM

Quick answer: The Stair tool adds a custom flight of stairs in just two clicks, automatically trying to fit whatever default settings you’ve configured. It builds single-flight straight, double-flight L-shaped, and double or triple-flight U-shaped stairs.

Creating a Straight Flight of Stairs

Select the Stair tool from the Quad.
Hover over a slab; the Stair Cursor appears and the slab highlights, marking the first step’s position (an invalid position turns the cursor red).
Choose Flip or type F to reverse the first step’s direction; choose Quarter-turn or type Q to rotate it 90 degrees; hold Ctrl with the Hotkey Assistant active to cycle through stair types. The cursor auto-flips or quarter-turns near a wall or slab edge, but only if Automatically flip/quarter-turn is enabled.
Left-click once positioned; the upper slab becomes transparent if it’s blocking your view.
Align the mouse perpendicular to the first step for a straight flight. A live blue preview follows the mouse dynamically, snapping to configurations matching your Preferred tread length setting and turning a darker blue once satisfied (other settings factor in too, just not into this specific snapping behaviour).
Left-click again; the flight of stairs creates, and a hole automatically generates in the upper slab based on the Head room setting.

Creating an L-Shaped Staircase

Select the Stair tool from the Quad.
Hover over a slab; left-click once the Stair Cursor is correctly positioned.
Move the cursor away from perpendicular to form an L-shape; the live preview snaps to the optimal configuration matching the dimensions set in the Stair dialog, displaying in a slightly darker shade.
Left-click once satisfied; the flight creates along with an automatically generated hole, which can itself be L-shaped depending on the upper flight’s length and the Head room setting (if the head room is too large to fit within the topmost flight alone, it extends into part of the second flight too).

Creating a U-Shaped Staircase

Select the Stair tool from the Quad.
Hover over a slab; left-click once the Stair Cursor is correctly positioned.
Move the cursor away from perpendicular to form an L-shaped stair first.
Press Ctrl (with the Hotkey Assistant, the HKA field in the Status Bar, on) to switch between an L-shaped and a U-shaped stair. Alternatively, align the last step with the first fixed step, entering a strip parallel to the first step automatically quarter-turns the last step, or type Q and press Enter to rotate the second cursor 180 degrees relative to the first.
Two U-shaped variants are available: one where the middle section includes steps, and one where it’s a landing between the two opposing flights. Switch between them by typing U and pressing Enter, or by pressing Ctrl to cycle through variants. A live blue preview follows the mouse, snapping to configurations matching your current settings and turning darker blue once satisfied.

Creating a Flight of Stairs in an Existing Opening

Useful when connecting floors through an opening that already exists, without needing a new one.

Starting from a slab edge:

Select the Stair tool from the Quad.
Hover the Stair Cursor near the edge of the slab; it snaps automatically to the outer side of that edge.
Create the flight of stairs using any of the procedures above.

Starting from the lowest point:

Select a starting point on the first floor.
Hover over the edge of the second floor’s slab; the Stair Cursor snaps to it automatically. Left-click to create the flight of stairs.

Editing a Flight of Stairs

Select a flight created with the Stair tool to adjust these parameters in the Properties panel:

Parameter	Controls
Height_Staircase	The overall height of the flight; fixed at the top, adjusted from the base
Stair_Width	The flight’s width. A green dot on the upper slab marks the insertion point when selected; centred, the flight widens from the middle, off to one side (against a wall, for example), it only widens away from that dot
Ideal_Riser_Height	The target riser height; the actual riser height calculates to divide as evenly as possible across the total height, as close to this ideal as it can
Step_Thickness	The step thickness; the upper face of each step is fixed, so thickness increases downward
Nosing	The horizontal overlap distance between subsequent treads
Length_StairFlight_0	The first flight’s length; decreasing it shortens the flight, with tread length and count updating based on the total flight length
Length_StairFlight_1	An optional second flight’s length, available for L-stairs and U-stairs only
Length_StairFlight_2	An optional third flight’s length, available for U-stairs only
Landing_Extension_Up	The landing’s length going down the first flight; the first flight stays fixed while the second adjusts to this value
Landing_Extension_Down	The landing’s length going down the second flight; the first flight stays fixed while the second adjusts to this value

Repositioning and Complex Editing

Reposition a flight of stairs created with the Stair tool using MOVE. For more complex edits, use BEDIT, the same block definition editor covered elsewhere in this hub, to edit its block definition directly; in BEdit mode, open the Mechanical Browser panel to view and edit every constraint that applies to the flight.

Frequently Asked Questions

What’s the difference between the two U-shaped stair variants? One has steps running through the middle section; the other replaces that section with a landing between the two opposing flights, switch between them by typing U and pressing Enter, or cycling with Ctrl.

Can I edit a flight of stairs after it’s already been created? Yes, adjust its parameters directly in the Properties panel, reposition it with MOVE, or make more complex edits via BEDIT and the Mechanical Browser panel.

Does the hole generated in the upper slab always match a single flight’s shape? Not necessarily, for L-shaped stairs, if the Head room setting is large enough, the hole can extend into part of the second flight, making it L-shaped too.

Where does the Stair tool’s live preview turn a darker blue? Once it snaps to a configuration matching your current settings, like the Preferred tread length setting for straight flights.