Walls that stay joined.
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.
Corners look after themselves
Two walls sharing an endpoint mitre automatically. Move either one and the corner recomputes — you are not maintaining the joint by hand, and it does not quietly come apart three edits later.
Where you want a butt joint instead, one click on the Joint tool toggles it. The wall you click is the one that gets cut; its neighbour runs through to the far face, so no step is left in the corner.
Openings are data, not holes
A window is a position, a size and a fill stored on the wall. The hole and the frame are regenerated every time the wall rebuilds — which is why an opening survives a stretched wall, a changed thickness or a re-mitred corner.
Position them from the centre or from the nearest edge, and type the clear gap. That is how the dimension arrives from the drawing: 900 from the corner, 1 200 between two windows.
Seven ways to edit
Join, extend, trim, stretch, stretch endpoint, offset — the operations a CAD user expects, working on walls rather than on lines.
Offset a whole chain and the copies mitre against each other; where a copy meets an original it stops at its face instead of overshooting by half a thickness.
Gable walls
Click the walls, then click the roof, and their tops follow the underside of it — including the ridge, with the profile sampled on both faces so the apex is sharp rather than rounded off.
The rest of it.
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.
Floors & stairs
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.
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.