Furniture Clearance Configurator

Previously, Generic Room Configurator II wrapped a kitchen array around a corner and let placement order decide what fits. I closed that post with a note to myself: “I need to add in the clearances though.” This is that post.

Here is the problem. A floor plan draws furniture as its footprint, and the footprint is the smallest honest number in the room. You’re checking a residential plan and every piece needs space to use it — to pull out a chair, open a drawer, walk past a bed. That space comes in two different kinds, and mixing them up is how a bedroom that fits on paper becomes a bedroom where the dresser drawer opens into the bed.

Three kinds of space

• Footprint (white in the drawing): what the furniture physically covers. A queen bed is 60 × 80 inches.
• Walking envelope (cyan): the band you need to move around it — in the first example, 24 inches at each side of the bed and 36 at the foot. Footprint plus walking envelope is what sizes the room.
• Opening envelope (dashed orange): the space something sweeps when you use it — a drawer pulled out, a door swung open, a chair pushed back. It is not added to the room. It has to fit inside the walking envelope, and while it is open it borrows that space from you.

What to watch

The drawing plays five examples. Drag the orange handle on the room’s right edge to set your own walking allowance: the footprint never moves, the room rectangle and its area follow the allowance, and the caption tells you what the opening envelopes are doing.

The queen bed covers 33.3 ft² of an 87 ft² room, about 38%. Everything else is the room doing its job. Step to the king and the room grows by 35.4 ft², to 122.4 — but that example changes two things at once: a mattress 16 inches wider, and 38-inch sides, the allowance the original wheelchair comparison used. Take them one at a time. A king with the queen’s 24-inch sides needs a 99.9 ft² room, so the bigger bed costs 12.9 ft²: 8.9 of mattress plus 4.0 of foot band stretched across the extra width. Widening the sides from 24 to 38 inches costs the other 22.5, and it costs the same with either bed in the room, because neither change touches the room’s depth. The allowance you choose costs about one and three-quarter times what the bigger bed does.

Now look at the foot of the bed. The dresser is 18 inches deep and its drawer pulls out another 18: exactly the 36-inch foot allowance. In the queen example the open drawer meets the corner of the bed, and the 32-inch door swing sits at the other end of the same band. Neither the dresser nor its drawer appears anywhere in the room arithmetic. Both live inside the walking envelope.

So does this queen room pass? No. The drawer is an opening envelope and belongs in the band, but the dresser is a footprint, and by the rule above it should have been added to the room. Because it wasn’t, it eats half of the foot band in the corner by the far side of the bed. The way around to that side is 18 inches wide with the drawer shut and zero with it open — less than the 24 inches this same example allows beside the bed. Give the dresser its own 18 inches of depth and the room becomes 9′ 0″ × 11′ 2″, 100.5 ft²: a clear 36-inch foot band again, of which the open drawer borrows 18.

The dining table makes the point harder. It covers 18 ft², and with 36 inches all around, the room is 108 ft² — the table is one-sixth of its own room. The 24-inch chair pull-out lives inside those 36 inches, which leaves 12 inches behind a pulled-out chair. Twelve inches is not a walkway; it is a place to turn sideways and apologize. At the 54-inch allowance from the wheelchair comparison, 30 inches remain behind the chair and the room is 180 ft², ten times the table. Drag below 24 inches and the pull-out runs past the room edge.

The seating group is the control: 42 ft² of furniture in a 132 ft² room with 30 inches on every side and no opening envelope drawn. It is the only example where the allowance means one thing.

The judgment

A configurator that stores furniture as footprints will undersize every room it touches. One that stores a single “clearance” per object is not much better: either it adds the drawer to the walkway and oversizes the room, or it ignores the drawer and you find out with your shin. Store three things per object — footprint, walking envelope, opening envelope. Size the room from the first two, then check the third against the walking band and against every other object. The dresser is the test case: the room arithmetic never noticed it.

The dimensions here are selected study values, listed under the drawing. They are not code minimums, and the 38- and 54-inch cases are the original’s wheelchair comparison, not an accessibility check.