Nesting in Rhino (the `OpenNest` command)

OpenNest also runs as a Rhino command — no Grasshopper needed. Type OpenNest on the command line, select your sheets, select your parts, and it nests them on a background thread (Rhino stays responsive) and bakes the result into layers, carrying each part's markings and Rhino object data along.

It installs with the same package as the Grasshopper components (Rhino Package Manager → search OpenNest), on both Windows and macOS — one install delivers the Grasshopper components and the OpenNest command.

Files to download:

⬇ OpenNest_Rhino.3dm — the example model used below.

How it classifies your selection

You make one mixed selection of parts and markup; OpenNest sorts it out automatically by geometry type and spatial containment — the same logic the Grasshopper Geometry components use:

You draw…	…it becomes
A planar surface (or Brep / NURBS surface / SubD / extrusion) standing on its own	a part — its outer loop is the border, its trimmed inner loops are holes (kept empty)
A closed curve standing on its own	a part (no holes)
Any closed boundary inside a part (surface / brep / subd / closed curve)	an attribute — kept verbatim and moved with its part
Any other geometry inside a part — text, open curves, hatches, points, dots	an attribute — moved with its part

So holes come only from trimmed surfaces (exactly like sheets), and anything sitting inside a part — a logo outline, an engraving, a label, a drilled feature — rides along as an attribute instead of being nested on its own.

Step by step

1 · Prepare the model

Lay out your parts (closed polylines or planar surfaces) with their markings on their own layers (here: Outline, Attributes, Attributes2), and place your sheet surfaces below. Type OpenNest.

Step 1 — parts with layered markings and two sheet surfaces; type OpenNest

2 · Select the sheets

At “Select SHEET(s) to nest onto”, pick the sheet surface(s) and press Enter. A surface's trimmed holes become keep‑out regions automatically.

Step 2 — select the two sheet surfaces

3 · Select the parts and set options

At “Select PARTS — markup … set options below”, click the command‑line options to configure the nest, then pick everything (parts and their markup) and press Enter. Click Engine to switch between NFP and Collision — the option list changes to that engine's settings.

Step 3 — select parts + markup with the full option menu

4 · Read the result

It solves on a background thread (the prompt shows live gen X / Y progress) and bakes into three layers, with a sublayer per source layer (name and colour copied) so your layer structure and by‑layer colours are preserved. If the parts don't fit, extra sheet copies are added to the right automatically.

Step 4 — nested result baked into opennest_outlines / opennest_attributes on two sheets

Output layers

Layer	Contents
`opennest_sheets`	the frame of each used sheet
`opennest_outlines`	placed part borders (+ holes), under a sublayer per source layer
`opennest_attributes`	placed markings (text, curves, breps…), each keeping its own colour / material / name, under a sublayer per source layer

Each placed part instance (outline + its attributes) is also put into its own group, so you can move a nested part as a unit.

Parameters

Pick the engine first; the options below switch to match it. Values are sticky for the Rhino session.

Engine = NFP (no‑fit‑polygon + genetic algorithm)

Option	Default	Description
Rotations	8	Orientation angles each part may try (360/n). More = tighter, slower.
Placement	Gravity	Strategy: Box · Gravity · Squeeze · BottomLeft.
Spacing	0	Gap kept between placed parts (model units).
Seed	30	Random seed (same seed = same result).
Iterations	10	GA generations to evolve — the result tightens each generation.
Mutation	10	GA mutation rate.
Population	10	GA population size.
AllRotations	Yes	Try every orientation per placement for the tightest pack (capped at 8).
ElementHoles	Fill	Nest smaller parts into larger parts' holes (Off / Fill).

Engine = Collision (penetration‑depth physics relaxation)

Option	Default	Description
Rotations	3600	Orientation angles each part may try; more = tighter, slower.
Seed	100	Random seed; change it if a run spills to a second sheet.
Starts	1	Multi‑start: run this many seeds and keep the densest.
Iterations	4000	Relaxation rounds; higher packs tighter but is slower.
Poles	48	Inscribed circles per part for collision tests; more = cleaner pack, slower.
ElementHoles	Fill	Nest small parts into larger parts' holes (Off / Fill / FillFirst).
Compact	BottomLeft	Post‑pack tightening slide (Off / BottomLeft / Multi).
Fit	OneSheet	OneSheet = fill a single sheet (overflow placed outside); AllParts = use as many sheets as needed.

Which engine?

NFP packs with exact no‑fit‑polygon math — best for clean, non‑overlapping layouts of polygonal parts. Collision uses an inscribed‑circle (Poles) surrogate that relaxes overlaps — great for dense packing, but very sharp corners can need more Poles. For guaranteed no‑overlap on spiky shapes, use NFP.

Notes

The boundary is taken exactly as drawn (no simplification), so placed parts never overlap their neighbours.
The solve runs on a background thread and keeps Rhino responsive (you can orbit/zoom while it works); the command line shows live progress.
Results are baked as real Rhino geometry (not a live preview), wrapped in a single Undo — so one Undo removes the whole nest.

Nesting in Rhino (the OpenNest command)