# Backyard Habitat Utility Pack — Revision 1

This free package contains three flat, support-free tools for backyard habitat
work:

1. A repeatable 50.8 mm exterior window-marker spacing stencil.
2. A six-size nominal nest-box entrance-opening measurement gauge.
3. A 100 mm metric field-photo scale with an orientation arrow.

All three unsplit parts share one guarded Bambu Lab X1C plate. They are
layout and measurement aids, not wildlife-safety devices or precision
metrology instruments.

## Important boundaries

- The window stencil is not a window treatment. It only positions centers for
  an actual exterior pattern or product.
- The opening gauge measures an existing or prototype opening. It does not
  choose a target species or prove that a box is suitable.
- The field-photo scale belongs beside tracks, leaves, feathers, or other
  signs. Do not put it on an animal, active nest, egg, or nestling.
- Revision 1 is digitally validated and has completed a warning-free Bambu
  Studio X1C slice, but it has not been printed, measured, weathered, or field
  tested.

## One-plate contents

### 50.8 mm window-marker stencil

- Twelve circular marker positions in a four-by-three grid
- 50.8 mm spacing in both axes
- 7.0 mm nominal apertures
- Engraved `50.8 MM` and `EXTERIOR` reminders
- Approximate part envelope: 165.4 x 114.6 x 2.4 mm

American Bird Conservancy currently recommends exterior patterns with
vertical, horizontal, and diagonal gaps of two inches or less. Its home
guidance also says dots or similar shapes should be at least one-quarter inch
in diameter and visible from a distance. This stencil uses a 50.8 mm grid and
7.0 mm nominal apertures, but the physical print and the applied marks still
need measurement. Pattern material, contrast, durability, full-pane coverage,
and exterior placement remain user responsibilities.

Source:

- https://abcbirds.org/strategies/solutions-for-homes/

Use the stencil on the outside surface of accessible glass. Fill or mark every
aperture, then overlap the previous row or column when shifting the tool so the
50.8 mm grid continues across the entire treated pane. Follow the selected
window-treatment manufacturer's instructions. Do not leave the printed
stencil attached to the window.

### Nominal nest-box opening gauge

The card has six comparison holes:

```text
25 mm  28 mm  32 mm
35 mm  38 mm  40 mm
```

The dimensions are deliberately species-neutral. Entrance requirements depend
on species, region, box design, and current authoritative guidance. Measure a
new or confirmed-empty box on the bench, then compare the result with the
current local plan you are following.

Do not approach or manipulate an active nest to use this tool. Cornell
NestWatch says observations should minimize disturbance, should never
jeopardize birds, and should not involve handling birds or eggs without the
required permits.

Sources:

- https://nestwatch.org/learn/how-to-nestwatch/code-of-conduct/
- https://nestwatch.org/learn/all-about-birdhouses/features-of-a-good-birdhouse/

### 100 mm field-photo scale

- 100 mm nominal baseline
- 10 mm tick interval
- Major ticks at 0, 50, and 100 mm
- Orientation arrow
- 5 mm lanyard hole

Place the scale on the same plane as a track, leaf, seed, feather, or other
non-living sign before taking the photograph. Point the arrow in a direction
you can explain in the observation notes. A high-contrast filament, or
contrast-filled engraving, makes the tool easier to read in photographs.

Never disturb wildlife, vegetation, tracks, or nest contents just to improve a
photograph. The scale supplies size context; it does not identify a species.

## Files

- `habitat-window-marker-grid-50p8mm.stl`
- `habitat-nestbox-opening-gauge.stl`
- `habitat-field-photo-scale-100mm.stl`
- `habitat-utility-pack-x1c-one-plate.stl`
- `habitat-utility-pack-x1c-one-plate.3mf`
- `habitat-utility-pack.step`
- `habitat-utility-pack-tools-preview.png`
- `habitat-utility-pack-x1c-plate-preview.png`
- `habitat-utility-pack-use-guide.png`
- `validation-report.json`
- `generate_habitat_utility_pack.py`

The 3MF contains three independent, millimetre-native, manifold meshes as
three separate build items. The STEP contains the same three solids in their
plate arrangement.

## Validated X1C slice

On July 27, 2026, the release 3MF completed a Bambu Studio 2.8.1.55 slice
with:

- Bambu Lab X1 Carbon
- Textured PEI Plate
- 0.4 mm nozzle
- `0.20mm Standard @BBL X1C`
- `PLA Basic`
- 12 layers at 0.20 mm
- No generated supports
- No mesh or plate-bounds warnings
- 14.10 m / 42.73 g estimated filament
- 7m15s preparation, 1h18m model printing, 1h25m total estimate

The slice is a software estimate, not a successful physical print. Re-slice
and inspect the file for the selected machine, material, plate, and current
software before printing. PLA is reasonable for an indoor dimensional trial.
PETG is a reasonable later trial when more handling and moisture tolerance
are useful.

## Physical checks required

1. Print once and inspect for lifted corners, elephant foot, sharp edges,
   unreadable engraving, or cracks.
2. Measure the stencil pitch in both axes with calibrated calipers.
3. Measure all six opening-gauge holes in at least two directions.
4. Compare the field scale's 100 mm baseline with a trustworthy ruler.
5. Test the stencil on disposable material before using it on glass.
6. Confirm the chosen window treatment's mark size, contrast, exterior use,
   glass compatibility, and full-pane coverage.
7. Use the entrance gauge only on a new or confirmed-empty box.
8. Trial the photo scale beside an inert object without disturbing habitat.
9. Observe cleaning, storage, sunlight, heat, and moisture deformation.
10. Stop using any tool that warps, cracks, delaminates, or no longer measures
    within the tolerance required for the task.

## What digital validation proves

The generated report checks that:

- Each individual STL is one watertight, winding-consistent component.
- The plate STL has three watertight components.
- The generic 3MF declares millimetres, contains three separate build items,
  and has no indexed boundary or nonmanifold mesh edges.
- The STEP imports as three solids.
- The placed parts do not overlap.
- The plate stays inside the nominal 256 x 256 x 250 mm X1C envelope and keeps
  the conservative front-left cutter corner clear.
- The nominal window grid, aperture count, gauge-size list, and photo-scale
  baseline match the generator constants.
- The release 3MF completes the recorded X1C Bambu Studio slice without
  supports, mesh warnings, or plate-bounds warnings.

It does not prove physical dimensional accuracy, window-treatment
effectiveness, species suitability, wildlife identification, weather
resistance, or a conservation outcome.

## Regeneration

From the parent `stl` folder:

```powershell
python .\generate_habitat_utility_pack.py
```

Edit the named constants near the top of the generator if a physical print
shows that a printer, material, or workflow needs compensation. Keep any
revised file labeled as a new tested revision rather than silently replacing
the nominal dimensions.
