Pivot Point

The big idea

A cube is 10 cm on a side, but it only ever measures from one spot: the point at its dead center. That point is the pivot point, and it is the cube's real address. The box around it is just something big enough for you to see and grab.

So the useful habit is simple: stop thinking of a cube as a box you are parking near a feature, and think of it as a single point you are dropping on that feature. The box is the handle; the pivot is the measurement.

Everything is measured from it

Location — the World and Local position on a cube's window is the position of its pivot, not a corner or a face.
Distance — a measurement between two cubes runs pivot to pivot, and the line drawn between them starts and ends at those two points. That is why every reading is described as center to center (see Action - Measure Distance Between Cubes).
Angles — the corner of an angle sits at the corner cube's pivot, and its two arms run to the pivots of the other two cubes (see Action - Read an Angle).
Level, slope, and pitch — all read from the rise and run between two pivots (see Action - Use the Spirit Level, Slope, and Pitch).

One consequence is worth spelling out: nothing is ever measured from a cube's surface. Resting a cube's face against a wall puts the pivot 5 cm out from that wall, and every number will say so. To measure the wall, put the pivot in the wall.

It is also what the cube turns around

Turning a cube spins it around its pivot, so the pivot stays exactly where you put it while the box swings about it. That is what makes it safe to aim first and turn second: you can place a cube on a feature, then rotate it to line up with a face or an edge, and the position you carefully set does not drift.

It also means turning a cube never changes a distance or an angle — those come from pivots, and rotating one leaves it where it was. Only moving a cube changes them (see Action - Move and Rotate a Cube).

The marker and the axes

You can draw the pivot as a small bright marker so you can see the exact spot you are aiming, and you can draw three colored axis lines radiating from it. Both are optional, and both live at the same point.

The axes are drawn along your chosen frame — world or local — rather than along the cube's own tilt, so they tell you which way the room or your reference runs from that point, not which way the cube is facing. See Action - Show the Pivot Point and Axes for the controls, and Concept - World Space and Concept - Local Space for the frames themselves.

In saved files

Saved work keeps the same convention. The written report lists each cube's pivot position, and the shape in a 3D or drawing export is cut through the pivot points themselves — the cubes you see in the file are markers around those points, not the thing being described (see Action - Save Your Data (TXT, SVG, 3D)).

Getting a pivot exactly where you want it

Show the pivot marker and place it by eye on the feature, then check it from a second angle — a point that looks right from one side can be well off along your line of sight.
When you know the number, type it instead of aiming: entering a position sets the pivot there exactly (see Action - Edit a Cube by Numbers).
For a feature you cannot reach or see, park local space on a cube you can place, and give the position from there (see Action - Define Local Space).