Tangent ratio height scaling

Tangent ratio scaling makes the crown or the pavilion of your stone taller or flatter, on its own, without touching the other half, the girdle's outline, or the index teeth. Every facet in that half changes its angle together, and the studio moves each one just enough that all its meets still meet — so the stone keeps the same silhouette and the same cutting sequence, only standing taller or squatter. A cutter reaches for this to fit a rough that came out shallower or deeper than the design expects, or to adjust a design's proportions for a stone of a different refractive index, without reworking every angle in the cutting instructions by hand.

Opening it

Choose Edit > Scale height from the menu bar.

The menu item is greyed out, with a tooltip explaining why, when there's no design loaded, or when another mode — editing a tier, resizing the girdle, the cutting assistant, or scale height itself — is already open. Finish or leave that mode first (its own Done, Cancel, or Escape), then open scale height.

What the screen shows

Once it opens, the top bar's mode readout, at the right-hand end, reads Scaling height — a reminder, from anywhere on the page, that you're scaling rather than looking at your finished design.

The stone turns to the same side-on view as the render pane's own Side button — crown up, the girdle seen edge-on — since that's the angle a height change actually shows up from. You can still orbit and zoom while the mode is open; whichever way you leave it, the view snaps back to wherever it was pointed before you opened scale height, even if you moved the camera in between.

On the left, the cutting instructions pane stays exactly as usual, so you can watch every tier's angle follow the gauges as you drag them. On the right, in place of the render settings, is the scale height panel:

• Two vertical gauges, Pavilion on the left and Crown on the right, each a tape you can drag, running from 0.25× to 4× and starting at 1.00×.
• A Fine button under each gauge, for slower, more precise dragging.
• Reset to 1×, under the gauges.
• Lock crown to pavilion, a switch under Reset.
• Cancel and Done, at the very bottom.

Scaling a half taller or flatter

Drag a gauge's tape downward to make that half of the stone taller (a larger ratio); drag it upward to make it flatter (a smaller ratio) — the same way pulling a strip of paper down brings its larger numbers to the centre line. The Pavilion and Crown gauges move independently unless you turn on Lock crown to pavilion (see below), so you can make one half taller while making the other flatter in the same session.

Reset and the lock

Reset to 1× puts both gauges back to 1× in one step — it leaves the lock switch as it was, since that's a separate choice. It's greyed out (with a tooltip saying so) whenever both gauges already read 1×.

Lock crown to pavilion ties the two gauges together: once it's on, dragging either one moves both by the same amount, to the same ratio. Turning it on immediately brings the crown to whatever ratio the pavilion is already at.

What happens to each tier's angle

Scaling a half changes every one of its tiers' angles by the same rule — a larger ratio turns a facet's angle up, a smaller one turns it down — while the table and the girdle keep their own angles exactly, and every tier's index teeth and notes are untouched. Continuing the 0.50× pavilion / 1.80× crown example above, the cutting instructions pane shows:

The pavilion tiers' angles all dropped (flatter, at 0.50×) and the crown tiers' angles all rose (taller, at 1.80×), while the girdle and the table stayed exactly where they were.

Confirming, cancelling and leaving

• Done keeps the scaled angles, as one step of the studio's own Undo.
• Cancel puts every tier back exactly as it was when you opened scale height, and records nothing.
• Escape does the same as Cancel — unless you're in the middle of typing an exact ratio, in which case it only cancels that typing, and the mode stays open. Press Escape again, with nothing being typed, to leave.

Either way out restores the view you had before you opened scale height, and the render settings panel comes back in place of the gauges.

Undo and redo

While scale height is open, Undo and Redo — the Edit menu's items, and Cmd+Z / Ctrl+Z and Shift+Cmd+Z / Ctrl+Shift+Z (or Ctrl+Y) — step through changes made to the two gauges and the lock only: a drag's release, a wheel notch, a key press, a typed value, a Reset, or a lock toggle each count as one step. This local undo has nothing to do with the rest of your edit history until you click Done.

Done folds the whole session into a single step of the studio's own Undo: pressing Cmd+Z / Ctrl+Z afterwards puts every tier straight back to how it stood before you opened scale height, in one step, whatever number of drags, scrolls or typed values it took to get there; Shift+Cmd+Z / Ctrl+Shift+Z brings the whole change back the same way.

Every gesture and shortcut

See also

• Editing facets by tier, for reading the cutting instructions pane and changing one tier's angle by hand instead of scaling a whole half at once.
• Girdle resizing, the other whole-design transform on the Edit menu — it changes the girdle's own thickness against the rest of the stone, rather than a half's height.