gridfinity

name	gridfinity
description	Gridfinity system knowledge: grid specs, print settings for baseplates and bins, anti-warp strategies, tile splitting for large drawers, and community best practices.

Gridfinity Skill

Design and print Gridfinity-compatible baseplates and bins using the gridfinity_extended_openscad library. Covers grid specifications, optimal print settings, anti-warp strategies, and tile splitting for large surfaces.

Grid Specification

Parameter	Value
Grid pitch	42 × 42 mm
Height unit	7 mm
Corner radius	3.75 mm
Magnet diameter	6.5 mm
Screw diameter	3.0 mm
Bin clearance	0.5 mm per side (built into library)

Library: gridfinity_extended_openscad

• Source: https://github.com/ostat/gridfinity_extended_openscad

• Local path: ../gridfinity_extended_openscad/ (relative to project root)

• Docs: https://docs.ostat.com/docs/openscad/gridfinity-extended

• Requires: OpenSCAD developer snapshot with manifold backend and textmetrics feature enabled

Key scripts (top-level)

Script	Purpose
gridfinity_basic_cup.scad	Standard bins/cups
gridfinity_baseplate.scad	Baseplates
gridfinity_item_holder.scad	Custom tool/item holders
gridfinity_tray.scad	Trays
gridfinity_lid.scad / gridfinity_sliding_lid.scad	Lids
gridfinity_drawers.scad	Drawers

Key modules (for use in custom designs)

Module	Purpose
modules/module_gridfinity_cup.scad	Cup/bin generation
modules/module_gridfinity_baseplate.scad	Baseplate generation
modules/module_gridfinity_baseplate_common.scad	Baseplate shared utils (outer dimensions, alignment)
modules/module_gridfinity_frame_connectors.scad	Seam snap connectors
modules/gridfinity_constants.scad	Grid pitch, magnet/screw sizes, corner radii

The combined/ directory has standalone single-file versions of each script (no use/include needed).

Using the library in OpenSCAD

The library path is relative to the project subdirectory, not the repo root. From a project like idasen-grid/:

// Import modules with 'use' (makes modules available without executing top-level code)
use <../../gridfinity_extended_openscad/modules/module_gridfinity_baseplate.scad>
use <../../gridfinity_extended_openscad/modules/module_gridfinity_baseplate_common.scad>

// Import constants with 'include' (executes top-level variable definitions)
include <../../gridfinity_extended_openscad/modules/gridfinity_constants.scad>

Path convention: Each project lives in its own subdirectory (e.g., idasen-grid/), so the library path needs ../../gridfinity_extended_openscad/ (up one to repo root, up one more to parent directory where the library lives).

Example: Custom baseplate

use <../../gridfinity_extended_openscad/modules/module_gridfinity_baseplate.scad>
use <../../gridfinity_extended_openscad/modules/module_gridfinity_baseplate_common.scad>
include <../../gridfinity_extended_openscad/modules/gridfinity_constants.scad>

// Parameters
drawer_width = 325;           // interior mm
drawer_depth = 385;           // interior mm
clearance_per_side = 0.2;     // shrinkage compensation

// Derived
usable_width = drawer_width - 2 * clearance_per_side;
usable_depth = drawer_depth - 2 * clearance_per_side;
grid_cols = floor(usable_width / 42);
grid_rows = floor(usable_depth / 42);

// Render
gridfinity_baseplate(
  num_x = grid_cols,
  num_y = grid_rows,
  outer_num_x = usable_width,
  outer_num_y = usable_depth,
  position_grid_in_outer_x = "center",
  position_grid_in_outer_y = "center"
);

Example: Basic bin

use <../../gridfinity_extended_openscad/modules/module_gridfinity_cup.scad>
include <../../gridfinity_extended_openscad/modules/gridfinity_constants.scad>

// 2x1 bin, 3 units high, with label
gridfinity_cup(
  width = 2,          // grid units wide
  depth = 1,          // grid units deep
  num_z = 3,          // height units (×7mm)
  position = "default",
  label_style = "left",
  fingerslide = "default"
);

Key parameters reference

Baseplates (gridfinity_baseplate):

• num_x, num_y — grid cells
• outer_num_x, outer_num_y — total outer dimensions in mm (grid + margins)
• position_grid_in_outer_x/y — "center", "near", "far" — grid alignment within outer boundary
• baseplate_style — "default" (weighted), "efficient" (cnc-friendly)
• corner_roles — [1,1,1,1] for rounded corners, 0 for flat (seam edges)
• seam_connector_snaps — maps to library's connectorSnapsStyle. Values: "disabled", "smaller", "larger"

Cups (gridfinity_cup):

• width, depth — grid units
• num_z — height in 7mm units
• label_style — "disabled", "left", "center", "right", "full"
• fingerslide — "none", "default", "rounded"
• wall_thickness — wall mm (default from library)
• num_compartments_x/y — internal dividers

Print Settings

Baseplates (recommended)

Baseplates are flat, functional parts with no cosmetic requirements. Optimize for speed and anti-warp.

.pi/skills/bambu-3mf/tools/create-3mf-cli.sh \
  baseplate.stl output.3mf \
  --setting layer_height=0.28 \
  --setting wall_loops=2 \
  --setting top_shell_layers=2 \
  --setting bottom_shell_layers=2 \
  --setting sparse_infill_density=10% \
  --setting sparse_infill_pattern=gyroid \
  --setting enable_support=0 \
  --setting brim_type=no_brim \
  --setting close_fan_the_first_x_layers=3 \
  --setting additional_cooling_fan_speed=0

Setting	Value	Rationale
Layer height	0.28 mm	~30% faster than 0.2mm; purely functional part, no cosmetic benefit from finer layers
Walls	2	Sufficient for baseplates; no structural load on perimeters
Top/bottom layers	2 / 2	At 0.28mm = 0.56mm solid. Enough for thin baseplate geometry; the cavity pattern handles the bottom profile
Infill	10% gyroid	Sweet spot: 8–15% recommended. Below 8% risks top-layer sag; above 15% wastes material
AUX fan	off (0)	Critical for anti-warp. Large flat PLA parts warp badly with AUX cooling. Community consensus for Bambu printers
Close fan first layers	3	No part cooling for first 3 layers — helps bed adhesion on large flat surfaces
Support	off	Not needed
Brim	off	Brim removal is impractical on baseplate geometry

Bins (recommended)

Bins have thin walls and need good layer adhesion. Slightly different priorities.

.pi/skills/bambu-3mf/tools/create-3mf-cli.sh \
  bin.stl output.3mf \
  --setting layer_height=0.24 \
  --setting wall_loops=2 \
  --setting top_shell_layers=3 \
  --setting bottom_shell_layers=2 \
  --setting sparse_infill_density=8% \
  --setting sparse_infill_pattern=gyroid \
  --setting enable_support=0 \
  --setting brim_type=no_brim

Setting	Value	Rationale
Layer height	0.24 mm	Community sweet spot: ~20% faster than 0.2mm, still clean walls. Use 0.2mm only for cosmetic parts
Walls	2	2 is the community minimum and sufficient for standard bins. Use 4 for tall bins (h≥6) to prevent vertical layer separation
Top layers	3	Enough solid coverage at 0.24mm (0.72mm); 4 layers is overkill for organizer parts
Bottom layers	2	2 layers = 0.48mm solid — sufficient for a flat floor; saves material vs 3
Infill	8% gyroid	5–10% is plenty for open-top bins. Below 5% risks top-layer sag; 15% wastes material. Gyroid = good omnidirectional strength
Support	off	Not needed for standard bins
Brim	off	Difficult to remove from bin geometry
AUX fan	default (on)	Fine for small/medium bins. Turn off (additional_cooling_fan_speed=0) for tall bins (h≥6) with large wall area

What BambuStudio handles automatically (no action needed)

• Arachne wall generator (default) — variable-width perimeters that fill gridfinity's thin walls cleanly, better than Classic for this geometry
• Scarf joint seam (default in recent versions) — hides seam lines on the curved bin corners automatically
• Travel / retraction optimisation — handled per-printer profile
• Part cooling — auto-managed; only override AUX fan for tall/large parts (see above)

Settings rationale (community sources)

• Layer height: 0.24mm is the community sweet spot for functional bins — faster than 0.2mm, cleaner than 0.28mm. Use 0.2mm only if surface finish matters. (Source: r/gridfinity, The Next Layer)
• Walls: 2 is the community minimum. For taller bins (h≥6), increase to 4 to prevent walls separating vertically — a known failure mode on larger bins. (Source: r/FixMyPrint)
• Top/bottom layers: 3 top / 2 bottom at 0.24mm = 0.72mm / 0.48mm solid — well above the functional minimum. 4+ layers is overkill for organizer parts. (Source: The Next Layer)
• Infill 5–10%: Below 5%, top layers can sag or warp mid-print. 8% is the safe lower bound. 15% wastes material for open bins with no structural load. (Source: The Next Layer, Portland CNC, r/gridfinity)
• AUX fan off (tall bins): The single most impactful anti-warp measure for PLA on Bambu printers. Critical for baseplates and large flat parts; less critical for small bins but recommended for tall ones. (Source: multiple Reddit/forum sources)
• No cooling first 3 layers: Standard anti-warp measure. Lets the first layers bond to the bed before cooling contracts them.
• Temperature: 220°C for PLA is at the high end but recommended for better layer adhesion, especially with larger nozzles or faster speeds. (Source: The Next Layer, CNC Kitchen)

Anti-Warp Strategies

Large flat gridfinity parts (baseplates, big bins) are prone to warping. Mitigations in priority order:

1. AUX fan off — set additional_cooling_fan_speed=0
2. No cooling first 3 layers — close_fan_the_first_x_layers=3
3. Textured PEI plate — good PLA adhesion (our default bed)
4. Higher nozzle temp — 220°C helps layer adhesion
5. Avoid brims — impractical on gridfinity geometry, use other strategies instead
6. Split large baseplates into tiles — reduces flat surface area per tile (see below)

Tile Splitting for Large Baseplates

When a baseplate exceeds the printer bed (256 × 256 mm on A1), split into tiles:

When to split

Dimension	Action
Width ≤ 256 mm, Depth ≤ 256 mm	No split needed — single piece
Width ≤ 256 mm, Depth > 256 mm	Split depth only → 2 tiles (front/back)
Width > 256 mm, Depth ≤ 256 mm	Split width only → 2 tiles (left/right)
Width > 256 mm, Depth > 256 mm	Split both → 4 tiles (front-left, front-right, back-left, back-right)

How the library handles tiles

The gridfinity_extended_openscad library handles multi-tile baseplates natively via these parameters on gridfinity_baseplate():

• position_grid_in_outer_x / position_grid_in_outer_y: Set to "near" or "far" to push the grid to one side, creating a margin on the opposite (outer) side. The library automatically places snap connectors on seam edges (no margin) and smooth borders on outer edges (margin present).
• corner_roles: Array of 4 values [near-x/near-y, near-x/far-y, far-x/near-y, far-x/far-y]. Set 1 for the outer corner (gets rounded), 0 for seam corners (flat for mating).
• seam_connector_snaps: Maps to library's connectorSnapsStyle. Values: "disabled", "smaller", "larger". "smaller" recommended — enough to align tiles without excessive snap force.
• seam_connector_clearance: Maps to library's connectorSnapsClearance. Default 0.2. Increase to 0.3 if snaps are too tight.

Tile alignment rules

Tile position	position_grid_in_outer_x	position_grid_in_outer_y	corner_roles
Front-left	"far" (margin left)	"far" (margin front)	[1, 0, 0, 0]
Front-right	"near" (margin right)	"far" (margin front)	[0, 0, 1, 0]
Back-left	"far" (margin left)	"near" (margin back)	[0, 1, 0, 0]
Back-right	"near" (margin right)	"near" (margin back)	[0, 0, 0, 1]

The library's $allowConnectors mechanism reads the alignment settings to determine which edges are seams:

• Edge with margin → outer edge → no connectors
• Edge without margin → seam edge → snap connectors placed automatically

Column/row split strategy

Split to keep tile dimensions well under 256mm. For a balanced split:

• Columns: Divide roughly in half. E.g., 7 columns → 4 + 3.
• Rows: Aim for front tile ≤ 256mm deep. E.g., 9 rows → 5 front + 4 back.

Tile outer dimensions = (tile_cells × 42) + margin where margin = (effective_dimension - grid_cells × 42) / 2.

Mixed tiles are compatible

Tiles printed with different settings (layer height, walls, infill) are fully compatible — they mate by snap connectors on the seam edges. Only the grid pitch and outer dimensions matter for fit.

FDM Tolerances

• Outer dimensions typically shrink 0.2–0.5 mm in FDM.
• Use clearance_per_side = 0.2 (default) for drawer fit. Increase to 0.3–0.4 if too tight.
• Snap connector clearance: connectorSnapsClearance = 0.2 default (mapped as seam_connector_clearance in our SCAD files). Adjust ±0.05 if too tight/loose.

Common Workflow

# 1. Design baseplate in OpenSCAD (parametric)
#    Set usable_width, usable_depth, clearance_per_side

# 2. Validate
.pi/skills/openscad/tools/validate.sh project/baseplate.scad

# 3. Preview assembly
.pi/skills/openscad/tools/multi-preview.sh project/baseplate.scad project/previews/assembly/ -D 'part="assembly"'

# 4. Export tile STLs
.pi/skills/openscad/tools/export-stl.sh project/baseplate.scad project/tile.stl -D 'part="front_left"'

# 5. Create 3MF with baseplate-optimized settings
.pi/skills/bambu-3mf/tools/create-3mf-cli.sh \
  tile1.stl tile2.stl output.3mf \
  --arrange --plate-names "Tile 1;Tile 2" \
  --setting layer_height=0.28 \
  --setting wall_loops=2 \
  --setting top_shell_layers=2 \
  --setting bottom_shell_layers=2 \
  --setting sparse_infill_density=10% \
  --setting sparse_infill_pattern=gyroid \
  --setting enable_support=0 \
  --setting brim_type=no_brim \
  --setting close_fan_the_first_x_layers=3 \
  --setting additional_cooling_fan_speed=0

# 6. Slice (optional — can also use BambuStudio GUI)
.pi/skills/bambu-3mf/tools/slice-3mf.sh output.3mf

References

• Gridfinity Extended OpenSCAD docs
• Gridfinity Tips & Tricks – The Next Layer — print settings, infill, layer count, warping
• Portland CNC – How to use Gridfinity — 0.2mm, 8% gyroid baseline
• r/gridfinity — community settings and warping solutions
• Bambu Lab Wiki – Retraction — travel/retraction optimization
• Bambu Lab Wiki – Seam Settings — seam position and scarf seam
• Bambu Lab Wiki – Wall Generator — Arachne vs Classic, when to switch
• r/FixMyPrint – Gridfinity walls separating — wall count fix for tall bins

Related Skills

• openscad (.pi/skills/openscad/) — Design and validate .scad models, generate previews, export STLs. Use this skill for all OpenSCAD operations; the gridfinity skill provides gridfinity-specific parameters and examples.
• bambu-3mf (.pi/skills/bambu-3mf/) — Create 3MF files with print settings and slice for printing. This skill's print settings section documents the optimal --setting overrides for gridfinity parts.