04 · Clearance offset

The 48-element dataset nested into two 510x635 sheets with a clearance offset (offset_geo / offset_sheets): the solve runs on offset geometry, and the original parts are drawn at the solved poses so the real clearance gaps are visible.

from pathlib import Path

from compas.data import json_load

from compas_nest import collision_solve
from compas_nest import nest_geo
from compas_nest import nest_sheets
from compas_nest import offset_geo
from compas_nest import offset_sheets
from compas_nest import opennest_collision
from compas_nest.viewer import animate

DATA: Path = Path(__file__).parent.parent / "data"
CLEARANCE: float = 0.1  # small gap (units) around every element and from the sheet edges/holes

# 1. the 48 element outlines (data/elements_strips.json) on a single 510 x 635 sheet
geo: nest_geo = nest_geo()
for outline in json_load(str(DATA / "elements_strips.json")):
    geo.add_part(outline)

sheets: nest_sheets = nest_sheets.from_size(510, 635, count=1)

# 2. offset for clearance (elements grow, sheets shrink), then solve on the offset geometry.
#    These settings replicate the OpenNest Grasshopper run that fits all 48 onto one sheet. The solve
#    is heavy (~10 min): 3600 orientations x 10000 rounds, multi-start. The original outlines are
#    nested with their full edges (the result is the original parts at the solved poses).
offset_g: nest_geo = offset_geo(geo, CLEARANCE)
offset_s: nest_sheets = offset_sheets(sheets, CLEARANCE)
handle: collision_solve = opennest_collision(
    iterations=10000,     # round budget for a tight single-sheet pack
    num_rotations=3600,   # fine orientation sampling (the elongated strips need it)
    seed=100,             # base RNG seed
    n_starts=6,           # multi-start: try several seeds, keep the densest (this is what fits all 48)
    part_holes_mode=1,    # "elements holes fill": nest smaller parts into larger parts' holes
    pole_max=48,          # collision-gradient fidelity (tighter packing)
    final_compact=2,      # multi-directional post-pack compaction (reclaims interior voids)
    fit_mode=1,           # "fit one sheet": pack everything onto a single sheet
    verbose=False,
).start(offset_g, offset_s)

# 3. animate the ORIGINAL parts at the solved poses (so the real parts show the clearance gaps)
animate(handle, geo, offset_s, save=DATA / "output" / "04_collision_dataset.json", park=-635.0)