Slabs, stairs, ramps and railings.
The parts of a building that are tedious to model and easy to get subtly wrong. Draw the walking line and the treads, landings, soffit and the opening in the slab above follow.
Slabs from the walls you drew
Click the walls that enclose a space, press Enter, and the outline follows their faces. It does not need a perfectly closed loop — the corners come from the faces, whatever the walls are justified to.
Openings are stored on the slab like openings on a wall. Move the slab and they travel; change its thickness and they are re-cut.
Stairs from a walking line
Draw the line from the bottom. Each turn makes a landing and the next flight runs perpendicular; click closer than the stair width and you get a U-turn with the landings merged.
Riser height is always derived from the storey height and the riser count, so it never drifts. A live 2h + b readout tells you when the flight has left the comfortable range.
One right-click cuts the opening through the slab above, matching the footprint — including the merged landing of a U.
Ramps to the gradients that matter
Fix the rise and let the gradient follow, or fix the gradient and let it climb as far as it climbs. Defaults come from Czech accessibility requirements, so a ramp drawn without touching anything is compliant by construction — and warns, rather than refuses, when a real building forces you outside them.
Railings that land on the steps
Pulled from the stair, the path follows the nosings, so posts stand on step edges instead of floating between them. Landings connect at their own level and U-turns go round the well.
Balusters, glass panels or horizontal bars, with a soft check against the 120 mm clear gap.
The rest of it.
Walls & openings
Draw a chain, and the corners mitre themselves and stay mitred. Windows and doors live in the wall as parameters, so nothing breaks when the wall moves.
Roofs
Not just rectangles. An L, a U, a plan with a wing — the hips, valleys and ridges are computed from the outline, so complicated roofs stop being a modelling exercise.
Structure
IPE, HEA, HEB, UPE, angles and hollow sections from the catalogue — with joints cut to follow the profile, not sliced flat.
Services
Ten systems, product catalogues, bends and tees that appear where they belong, and connection ports that snap to the fixtures.
Documentation
Plans per storey, named sections, hatching by material at your drawing scale, schedules, and a LayOut file at the end of it. This is where the SketchUp ecosystem stops.
IFC
Material layers, openings linked to their fills, quantities computed from the geometry — and a check that stops two elements collapsing into one in the viewer.