Press U — the toolbar calls it Split level (sunken or raised floor) — then click the corners of the area whose floor sits at a different level and press Enter to close it. A sunken living room, an entry landing, the uphill half of a terraced ground floor. It starts one step down; the panel does the rest.
Everything the zone does not cover stays at the storey’s own level, so a plan with no zones is identical to one drawn before split levels existed.
Zone or storey?
A jump you take in a few steps inside one space is a zone. A jump with a real stair between separately drawn wings is another floor — add a storey at the level you want and trace this one under it.
The panel
| Field | What it does |
|---|---|
| Step | The signed offset from the storey’s floor level, −3000 to 3000 mm. Negative is sunken, positive is raised. |
| Slab thickness | The construction of the zone’s own slab. |
| Steps on edge | One button per boundary edge. Turn an edge into a flight of steps instead of a plain upstand. |
| Riser (target) and Going | The step geometry along those edges. The riser is a target — the real one divides the drop evenly. |
| Level tag on plan | The ±0.00 / −0.60 tag. It reads in metres from project zero, not from this storey, and it is derived — there is nothing to keep up to date. |
The boundary is layered
Along the edge of a zone, three things can happen, and the drawing decides which:
- An edge you marked under Steps on edge becomes a flight of steps.
- An edge where you drew a real wall yields to that wall — the generator stops where your wall runs, so a wall along the boundary is not doubled by an upstand.
- Everything else gets a generated upstand.
What a wall on the boundary does
A wall spanning two levels runs from the lowest slab under its footprint up to its height above the highest one. It is taller on the low side, and the heads of its doors and windows stay in line across the storey — which is what you want, because a wall along the boundary of a sunken room is the normal case.
Furniture and stairs stand on whichever slab is under them. A roof does not move: its wall plate is measured from the storey’s floor level, so the raked profile is lifted by the same amount as the zone.
What this doesn’t do
- The zone is flat. It is a slab at one level, not a ramp — there are no ramps yet.
- No per-edge upstand overrides. An edge is a step or an upstand; the upstand’s build-up is not set edge by edge.
- It is not terrain. For ground that falls across a site, see ground level and surfaces.
Next
Adding a storey for a real second floor, and stairs if the jump wants a proper flight.