Definition
What it means.
- Turning radius
- A hallway wide enough to carry an item straight can still trap it at a 90° turn, because the item’s diagonal, not its width, is what sweeps through the corner. The turning radius captures that sweep: the longer and less flexible the item, the more hallway and approach width the bend demands. ItemFits models the corner as a swept envelope to decide whether the turn is makeable.
In depth
The fuller picture.
The corner is decided by the diagonal
Down a straight hallway, only an item width has to fit. At a 90 degree turn the rules change: the item has to rotate, and the span that sweeps through the corner is its footprint diagonal, which is always longer than its width. A long, rigid bookcase can travel a 36 inch hall with ease and then jam solid at the bend, because its diagonal needs more room than the corridor offers on either side of the corner.
Length and rigidity make the turn harder. A longer piece has a longer diagonal, and a rigid one cannot flex to shorten it, so the bend is the place a move most often fails even when both approaching halls are wide enough. ItemFits models the corner as a swept envelope, rotating the item footprint through the turn, rather than just comparing widths.
Measure it
How to measure.
In practice
How it shows up.
A long rigid bookcase may travel a 36-in hallway easily yet jam at the 90° turn, which is the case ItemFits flags through its turning-radius check.
How it is computed
The math behind it.
r ≈ diagonal of the item’s footprintThe binding span at a 90° turn is the item’s footprint diagonal, not its width.
Go deeper
Related terms and tools.
Frequently asked
Questions we keep getting.
Why can an item fit a hallway but not its corner?
Down a straight run only the item’s width matters; at a corner its longer diagonal must sweep through, so the turn needs more room than the run.
01What makes a turn harder for furniture?
Length and rigidity. A longer piece has a longer footprint diagonal to swing, and a rigid one cannot flex to shorten it.
02Does the width of both hallways matter at a turn?
Yes, the item sweeps between the two corridors, so the room on each side of the corner together with the item diagonal decides whether the turn is makeable.
03