stlbench 0.2.3

STL preparation toolkit for resin 3D printing: uniform scaling, bed packing, fill, autopack.

stlbench

STL preparation toolkit for resin 3D printing.

stlbench takes STL files and prepares them for SLA/DLP printers: uniform scaling to fit the build volume, packing parts onto rectangular print plates, filling the bed with copies, and combined scale-and-pack in one step. Supports are not generated -- use your slicer (Lychee, Chitubox, PrusaSlicer, etc.) after export.

Installation

pip install stlbench

(scipy is a required dependency for voxel hollowing with scale --hollow; install uses binary wheels on supported Python versions — see PyPI.)

Development install

git clone https://github.com/NikitaDmitryuk/stlbench.git
cd stlbench
poetry install --with dev

Quick Start

Run stlbench --help for the same command cheatsheet (copy-paste friendly).

# Inspect model parts
stlbench info -i ./parts -c configs/mars5_ultra.toml

# Scale all parts to fit the printer
stlbench scale -i ./parts -o ./scaled -c configs/mars5_ultra.toml

# Pack scaled parts onto plates
stlbench layout -i ./scaled -o ./plates -c configs/mars5_ultra.toml

# Scale + pack all on one plate in one step
stlbench autopack -i ./parts -o ./packed -c configs/mars5_ultra.toml

# Fill the bed with copies of a single part
stlbench fill -i ./part.stl -o ./filled -c configs/mars5_ultra.toml

Or specify the printer inline without a config file:

stlbench scale -i ./parts -o ./scaled -p "153.36,77.76,165"

Commands

info -- Analyze models (read-only)

stlbench info -i ./parts -c configs/mars5_ultra.toml

Displays a table with AABB dimensions, volume, vertex/face counts, whether each part fits the bed, maximum scale factor, and how many copies would fit (fill). No files are written.

scale -- Uniform scaling

stlbench scale -i ./parts -o ./out -c configs/mars5_ultra.toml

Computes a single scale factor so that every part fits inside the printer build volume. The largest part determines the factor; all parts share the same scale. Supports two methods: sorted (default) and conservative.

Key options: --dry-run, --no-upscale, --method, --orientation free, --hollow, --post-fit-scale.

layout -- Pack parts onto plates

stlbench layout -i ./scaled -o ./plates -c configs/mars5_ultra.toml

Arranges already-scaled STL files onto rectangular print plates using rectpack. Exports plate_01.stl + plate_01.json with positions. Multiple plates are created if parts do not fit on one.

Key options: --dry-run, --gap-mm, --algorithm shelf|rectpack.

autopack -- Scale + layout on one plate

stlbench autopack -i ./parts -o ./packed -c configs/mars5_ultra.toml

Binary-searches for the maximum scale factor at which all parts fit onto a single plate simultaneously. Combines scale and layout into one step with a different goal: all parts on one plate, not each part fitting individually.

Key options: --dry-run, --gap-mm, --margin, --post-fit-scale.

fill -- Maximum copies of one part

stlbench fill -i ./part.stl -o ./filled -c configs/mars5_ultra.toml

Packs as many copies of a single STL file as possible onto one plate. Useful for batch printing identical parts.

Key options: --scale (scale the part to fit before filling), --dry-run, --gap-mm.

hollow

stlbench hollow prints a short reminder: hollowing is optional and runs only with scale ... --hollow plus [hollow] in the TOML.

config init -- Create a starter TOML

stlbench config init -o my_printer.toml

Writes a commented profile with the same defaults as configs/mars5_ultra.toml (example resin printer sizes, scaling, gap, hollow params). Use --stdout to print without saving, or --force to overwrite an existing file.

Configuration

Printer profiles are TOML files. See configs/mars5_ultra.toml for a complete example (ELEGOO Mars 5 Ultra), or generate one with stlbench config init.

Key sections:

Section	Purpose
[printer]	Build volume: width_mm, depth_mm, height_mm
[scaling]	bed_margin, post_fit_scale
[packing]	gap_mm between parts on the bed
[hollow]	wall_thickness_mm, voxel_mm for scale --hollow

Orientation (axis / free) and rotation sample count are not in TOML: use scale --orientation and scale --rotation-samples. With free, orientation matches the same printer-axis search as layout (permutation × random rotations), but scale picks the candidate that maximizes the group scale factor (layout still minimizes XY footprint for packing). Plate placement is only in layout. Default layout algorithm (rectpack vs shelf) is set via layout --algorithm.

Examples

See examples/README.md for a full walkthrough using the included Gendalf model (3 parts tracked via Git LFS).

Package Structure

Module	Purpose
stlbench.cli	Typer CLI application
stlbench.core	Scale factor computation and orientation
stlbench.config	Pydantic schema + TOML loader
stlbench.packing	Shelf and rectpack algorithms
stlbench.export	Plate STL assembly and JSON manifest
stlbench.hollow	Voxel shell hollowing (scale --hollow)
stlbench.pipeline	Command runners (scale, layout, fill, etc.)

Limitations

• Boolean and voxel operations are sensitive to non-manifold STL. For complex models use a mesh repair tool first.
• Hollow shells in this package are a simplified voxel approach; for production use your slicer's built-in hollowing.
• Very new Python releases may lack a scipy wheel yet; use a version listed for your platform on PyPI or wait for upstream wheels.

License

MIT