StairBuilder

Install

1. Install from Fab, or copy StairBuilder into your project's Plugins/ folder.
2. Edit → Plugins, enable StairBuilder and restart.

Draw stairs

1. Choose Stairs in the Level Editor's mode dropdown. The Draw tool starts automatically.
2. Click the bottom of the stairs (the floor where the first step starts).
3. Move to the top edge. A live preview shows the steps, riser, tread and slope. Problems show in red.
4. Click. A Stairs actor is created, fitted to the space, and selected.

Tool options (left panel): Width, Preferred Riser Height, Railings, Solid, Snap To Grid, and the step and slope limits for the live check.

You can also place Stair Builder from the Place Actors panel (search "Stair") and edit everything by hand.

Edit stairs

Select the actor. Every change rebuilds instantly.

Turning stairs

For L and U shapes, the landing counts as one riser. With 11 steps, you get 5 steps, then the landing, then 5 steps.

Custom meshes

Each piece is stretched to fill its box. Model steps as a 1×1×1 block (any size works, since it gets fitted) with the pivot anywhere. For posts, a cylinder or square post standing on Z. For rails, a bar along X.

Collision

• Steps use the step mesh's collision (the engine cube has box collision).
• Smooth Ramp Collision adds a thin hidden ramp per flight that only blocks Pawns. Characters walk up smoothly, while traces, projectiles and the camera still hit the real steps.
• If the slope is steeper than the walkable angle, the Warnings field tells you. Deepen the treads or lower the rise.

Baking

To turn stairs into a single static mesh, select the actor and use Actor → Merge Actors (or Convert to Static Mesh).

Blueprint

• Rebuild() regenerates the instances.
• Fit Between(Bottom, Top) places and sizes a straight staircase between two world points.
• All properties are BlueprintReadWrite, so you can generate stairs procedurally at runtime too.