GemDiagram Docs

Developer Overview

The Developer is where you design gemstone cuts. You start with a preset or a blank canvas, adjust tiers by angle and cut distance, control symmetry, and preview the 3D result in real time.

The design workflow

  1. Pick a starting point: Load a preset (Round Brilliant, Step Cut, etc.) or start Manual Mode blank.
  2. Adjust tiers: Each tier is a ring of facets around the stone. Change its angle (how steeply it tilts), distance (how far from center), and index positions (which spots around the stone it occupies).
  3. Control symmetry: Tell the editor how many times the design repeats around the stone (4-fold, 8-fold, etc.) and whether it's mirrored.
  4. Preview: The 3D view updates live as you tweak values.
  5. Save: Download as a .facet file, or export to PDF.

Note

Tier editing and saving/exporting require a Starter plan or higher. The Free plan lets you preview the pre-loaded gems and trace light in Ray Studio — see Accounts, Plans & Billing.

Two editing modes

Guided Mode (the wizard) walks you through the pavilion, crown, and girdle step by step. Best for learning or making a few targeted edits to a preset.

Manual Mode (the tier editor) shows every tier in a list — you can add, delete, or fully customize each one. Best for building from scratch or making broad changes.

The four tiers groups

Every design has tiers arranged in three groups (plus a fourth that's always there):

  • Pavilion: The facets below the widest edge, bouncing light back up.
  • Crown: The facets above the widest edge, the ones you see looking down into the stone.
  • Girdle: The thin band at the stone's widest edge, where crown and pavilion meet.
  • Table (at the top): A special single-facet tier at the very top of the crown, usually small and flat.

See Faceting Workflow for what angle, the index wheel, and cut distance actually mean.

Live 3D preview

As you adjust tiers, the stone updates in real time. You can:

  • Rotate by clicking and dragging the viewport.
  • Zoom with the scroll wheel.
  • Snap views: Use the Iso, Top, Bottom, Front buttons for preset angles.
  • Toggle overlays: Show tier colors, edges, or just the polished surface.
  • Switch render modes: Solid (instant, flat color) or Realistic (slow, full ray tracing with refraction and dispersion).

Proportions controls

Beyond angle and distance, you can adjust the whole crown or pavilion using a scale slider — this nudges every facet in that side up or down together without changing angles. Useful for fine-tuning how deep or shallow the stone looks without reworking every tier individually.

When to use Developer vs. Guided

  • Guided: You're new, or you want step-by-step guidance for a simple design.
  • Manual: You're building something custom, or you want fine control over every tier.

You can switch between them: a design saved from Guided opens in Manual, and vice versa.