Gridfinity

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

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)

Key modules (for use in custom designs)

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

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

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

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

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.