Plan a print project

---
name: plan-a-print-project
description: >-
  Turn an idea for a 3D-printed object into a plan someone can build from:
  purpose, dimensions, printer and material, the files to make, and the checks
  that decide when it is done. Use at the start of any print project, before
  modelling, when the brief is a sketch, a photo, a sentence, or a broken part.
title: Plan a print project
date: 2026-09-24
author: Benchy
tags: [3d-printing, planning, fdm, skill]
license: MIT
metadata:
  version: "0.1.0"
  schemaVersion: 2
  surface: "Any agent · no account needed"
---

# Plan a print project

A print project fails most often before anyone opens a modelling tool: a
missing measurement, a part too big for the plate, a material that softens in
a hot car. This skill produces a one-page plan that settles those questions
first.

## Ask before you plan

Get answers to these. Where the user does not know, write the question into
the plan as open; never invent a measurement.

1. **What it does.** What the object holds, joins, protects or replaces, and
   what happens if it breaks. If a failure could hurt someone (load-bearing,
   child use, food contact, heat or electricity), say so plainly and recommend
   a qualified review. This skill does not certify safety.
2. **Size and fit.** The overall dimensions in millimetres, and every
   dimension that must mate with something else (a screw, a shelf, another
   part), with its tolerance. Ask for calipers readings over estimates.
3. **Printer.** Make and model, build volume, nozzle diameter, and whether it
   has an enclosure or multi-material.
4. **Material.** What the user has, and what the use needs: PLA for indoor and
   rigid use, PETG for tougher parts and some outdoor use, ASA or ABS for heat
   and UV (these need an enclosure), TPU for flexible parts.
5. **Where it lives.** Indoors or outdoors, temperature range, sunlight, water.

## Write the plan

Return a short document with these sections, in this order:

- **Brief:** one paragraph: the object, its job, and who uses it.
- **Constraints:** a table of dimensions, tolerances, printer and material,
  each marked _measured_, _given_ or _open_.
- **Approach:** how many parts, and why. Split a part when it is larger than
  the build volume, when a split removes most of the supports, or when
  layer direction would put the load across layers instead of along them.
- **Print orientation:** for each part, which face sits on the plate and where
  supports are likely.
- **Files to produce:** an editable source (for example a `.blend` or CAD file),
  a print file (`.3mf` preferred, since it keeps units and plate settings;
  `.stl` accepted), and a short notes file.
- **Done when:** the checks that decide completion, such as a test print of the
  critical fit, measured dimensions within tolerance, and the part doing its
  job for a stated time.
- **Open questions:** everything still marked _open_.

## Hand off

The next step is modelling (see `prep-a-model-in-blender`) and then slicing
(see `print-prep`). Keep the plan beside the files: if the user keeps projects
in Benchy Box, the plan belongs in the same packet as the model, where it
travels with the files when the model is published to World.

## What this skill does not do

It does not model, slice, or print. It does not decide that a part is safe.
It reports what was measured and what was assumed, and keeps the two apart.