Chapter 3: Inside the Interactive Slicer — Dials, Masts & Meetpoints

In Chapter 2, you used the Interactive Slicer to cut a Round Brilliant. Now let’s open the hood on every dial, button, and mode inside the Slicer so you can design or modify any gemstone—from simple step cuts to intricate asymmetric fantasy cuts—without touching the keyboard.

[!IMPORTANT] Always Slice in Palette or Mono View Mode The Slicer’s translucent 3D cutting-plane disc, vertex depth-snap guides, and clickable golden meetpoint diamonds (♦) are displayed in Palette and Mono modes. When the viewport is set to Raytraced, ASET, or BDPT, ProFacet shows a yellow reminder banner at the bottom of the Slicer (Interactive slicer only works in Monochrome or Palette mode).

1. The Top Precision Dial Deck

The top bar of the Slicer is your digital index head. It controls the gear tooth count and how your active cut repeats around the 360° dop axis:

A. The Gear Hub (96)

• Click the machined Gear Wheel on the far left to cycle through standard faceting machine gears: 32, 64, 72, 80, 96 (default), and 120.
• When you switch gears, ProFacet updates the tooth ticks on the IDX and MIR drums and recalculates the valid divisors on the SYM drum automatically.

B. Dial Mode vs. List Mode

• Dial Mode (Default): Uses the three horizontal cylindrical Vernier drums (IDX, SYM, MIR) to generate symmetric tooth loops.
• List Mode (Explicit Index List): Click the Dial button to switch to List mode whenever you want to cut an asymmetric stone or an arbitrary subset of teeth (such as [0, 24, 48] without 72). In List mode, you can type tooth numbers directly or click individual teeth around a visual gear ring.
• ? Button (Symmetry Assistant): Opens the Symmetry Assistant to reverse-engineer IDX, SYM, and MIR from any printed tooth sequence.

C. The Three Vernier Drum Dials (IDX, SYM, MIR)

You can click and drag any drum horizontally, scroll your mouse wheel while hovering over a drum, or click any visible number on the drum scale to snap to it:

2. The Two-Column Slicer Workbench

Beneath the Dial Deck, the Slicer is split into the Tiers Table & Action Bar on the left and the Vertical Angle & Depth Masts on the right:

Left Column: The Tiers Table

1. Header Bar (TIERS & 02-06 | mp() Switch):
   • CAM 2 + 6 Badge: Shows the count of CAM preform tiers (2) plus permanent faceted tiers (6).
   • 02-06 vs. mp() Toggle:
     • 02-06 (Cutter View): Displays the exact sequence of gear teeth (96-12-24-36-48-60-72-84) you dial at the machine.
     • mp() (Formula View): Displays the symbolic FSL depth/meetpoint target (: gp() + girdle x8 m 3) so you can verify how each tier is anchored geometrically.
2. The Green CAM Row:
   • Summarizes your stone's starting outline (Round 43° · ×16, RectTr 1.4× · 43° · tr 0.28, etc.).
   • Click the green CAM row at any time to open the CAM Preform Studio and change the stone's shape, aspect ratio, or corner truncation!
3. In-Place Editing of Existing Tiers (P1, P2, C1…):
   • Click any committed tier row in the table to edit it in-place! The row highlights, and its angle, depth, meetpoints, and drum dials load into the Slicer controls. Adjust the angle or meetpoint and click Commit ✓ to update that tier (and automatically recompute all downstream tiers that depend on it!), or click Cancel to discard your changes.
   • The ± Optimization Toggle: Click the ± button on the right edge of any tier row to mark (or unmark) that tier's angle with a +/- optimization range for the GPU Optimizer.
4. The Dashed +LIVE Row:
   • The bottom dashed row (+C4 37.50° 96 LIVE) shows the uncommitted tier you are currently previewing on the 3D stone.

3. How ↓ Jump, +Meet, and +girdle Work Together

At the bottom of the Tiers table sit four geometry buttons that replace manual depth guesswork:

4. Edgepoint (Edge) Mode — Cutting Fractionally Along a Ridge

What if you are designing a step cut, a portrait stone, or a fantasy cut where a new tier does not meet an existing corner, but instead needs to slice 40% or 50% of the way along an existing ridge between two facets?

Clicking Edge opens the Edgepoint (ep) Panel:

1. Click Edge in the bottom action bar.
2. Select the two adjacent facets (Facet 1 and Facet 2) that share the ridge—or click the ridge directly in the 3D viewport.
3. Drag the Ratio slider (0.00 to 1.00) to position the cut anywhere along that ridge (0.50 = exact midpoint).
4. Click Commit ✓—ProFacet writes a parametric ep(edge(Facet1, Facet2), ratio) expression into your script that stays locked to that proportional position even if the stone is resized or optimized!

5. Right Column: Crown | Pavilion & Vertical ANGLE / DEPTH Masts

• Crown | Pavilion Switch: Determines whether 0°–90° angles cut from above (Crown, +Z) or from below (Pavilion, -Z).
• ANGLE Mast (0.00° – 90.00°):
  • Drag the vertical slider thumb, type an exact number into the top readout box, or click Fine at the bottom of the mast to open a 0.01° precision jog wheel.
  • θc Critical Angle Pill: Displays arcsin(1 / RI) in degrees (θc 34.6° for Sapphire, θc 40.5° for Quartz) right at the base of the ANGLE mast.
• DEPTH Mast (Top – 0):
  • Drag the vertical depth thumb whenever you want to position a cut freely in space (Style 1: Angle + Depth) or preview how deep a cut will go before clicking ↓ Jump or +Meet.

Next, let’s explore how to change the outer shape of your stone into Ovals, Emeralds, Pears, Cushions, Hearts, and Shields in Chapter 4: Shaping the Outline — The CAM Preform Studio.