Trellis

Trellis

The Trellis command builds a crossing-prong setting: pairs of prongs that bow outward from the gem and cross each other on their way down to a ring below, giving the classic trellis silhouette. Select one or more diamonds or gemstones — unsupported shapes (Pear, Heart, Trillion, Triangle, Calf, Coffin, Baguette) are filtered out of the selection. A default ring curve is generated automatically under each gem; you can instead pick your own curve from the panel’s Selection section, as long as it lies below the gem.

The command panel has a Selection section for the ring curve, and a Parameters section split into two tabs: Prongs and Upper Rail.

Selection

Use the object selector to pick an existing curve as the ring the prongs land on. Leave it unselected to use the automatically generated default curve, positioned under the gem at the Height distance set in the Prongs tab.

Prongs

• Top Profile: The prong’s shape near the gem — Circle (a plain swept/piped prong) or Claw (rebuilt as a claw with its own cap controls).
• Bottom Profile: The cross-section where the prong lands on the ring — Circle (rounded end), Square (rectangular, sized by Width / Height) or Custom (each prong ends in half of a curve you pick from your assets; two adjacent prongs reconstruct the full profile together).
• End Profile Curve (Custom only): The closed curve used for the custom bottom profile.
• Profile Start: Fraction of the prong length, from the gem side, where the round cross-section starts morphing into the Bottom Profile shape — lower values give a longer, gentler transition.
• Cross Height: Raises or lowers the point where the crossing prongs meet, without moving their ends.
• Width / Height: Dimensions of the rectangular bottom section (Square bottom profile only).
• Diameter: The prong tube diameter.
• Gem Inside: Radial offset of the prong from the girdle.
• Over Girdle: Vertical offset of the prong top above the girdle.
• Top Vertical: Additional vertical offset near the top of the prong.
• Birth Separation: Y-axis separation of the point where each pair of prongs originates.
• Bend Inside: How far the prongs bend inward as they cross.
• Distance: Y-axis separation applied to where the prongs land on the ring — separates the bottoms of the trellis without moving the tops.
• Opening: The crossing angle between each pair of prongs.
• Height: Vertical gap between the gem’s girdle plane and the top of the auto-generated default ring curve (ignored when you pick your own curve).
• Rotate: Rotates the whole gemset 90° around the gem’s vertical axis, so the same setting can serve an oval stone whether its long axis runs along the finger or across it.
• Extension: Extra prong material added above the gem in Manufacturing mode, ignored in Render mode.

Claw (Top Profile = Claw): Cap Distance pulls the claw apex toward the gem’s center, Cap Height raises or lowers it, Tip Width sets the apex thickness as a fraction of the tube, and Tip Smoothness softens the body-to-cap transition. Face Tangent switches the claw direction between following the girdle’s local tangent (on) and pointing straight at the gem’s center (off) — off tends to look cleaner on cornered gems like Princess.

Prong 1 and Prong 2: Each of the two crossing prongs has its own Bulge Start, Bulge End and Middle Offset, letting you fine-tune the two halves of the crossing independently.

Upper Rail

• Enabled: Turns the upper rail on or off.
• Mode: Circle for a round rail, or Custom Shape to use your own profile asset.
• Metal profile: Pick the rail’s cross-section from your profile assets using the preview selector.
• Width / Height: Dimensions of the rail cross-section.
• Under Girdle: How far the rail sits below the girdle.
• Rotation: Rotates the rail’s cross-section.
• External X / External Y: The rail’s outer dimensions in millimeters, measured edge to edge.
• Chamfer: Enables an internal chamfer on the upper rail, with a Chamfer Offset to control its size — useful to prepare the seat for the gemstone.