Builder's toolkit: full-size station moulds, profile and transom patterns, and a printable table of offsets

CHANGELOG.md

@@ -2,6 +2,35 @@
 
 Versions follow [semantic versioning](https://semver.org/), with `0.x` meaning that anything may change.
 
+## Unreleased
+
+- Builder patterns: `seacraft templates hull.fef -o moulds.pdf --skin-mm 6` cuts full-size station moulds from the
+  refined hull, moved in by the skin thickness along the surface normal, with the mould face that goes on the
+  station line, the largest bevel, waterlines, the design waterline and optional strongback legs or half moulds.
+  `--profile` adds the backbone and `--transom X,RAKE` a raked transom drawn true in its own plane. A PDF is tiled
+  over A4, A3, Letter or any paper size with join marks, a map page and two 100 mm check rules, or put one pattern
+  on each page (`--single-page`); `.svg` and `.dxf` (millimetres, layered) give one drawing. The patterns are
+  checked against closed-form shapes (cylinder, cone, box, raked plane) and against poppler's rendering of the
+  PDF (100 mm drew as 1000 px at 254 dpi). Nobody has printed and measured a set yet, and the PDFs have not been
+  opened on Windows or macOS. [`docs/building.md`](docs/building.md) is the builder's guide.
+- `seacraft offsets --pdf offsets.pdf [--imperial]` prints the table of offsets in millimetres above the keel, and
+  with `--imperial` the same tables in feet-inches-eighths.
+- `seacraft offsets --json` keeps its standard output to the JSON table when it also writes `--pdf`, `--html` or
+  `--csv`: the "wrote" lines now go to standard error.
+- GUI: File ▸ Builder templates… previews the page count on a background job and exports the patterns; File ▸
+  Export ▸ Offsets table PDF…. The control channel gains `build.templates`, `model.export` format `offsets_pdf`
+  (with `stations`, `waterline_steps`, `buttock_steps`, `level`, `imperial`) and `ui.set` `templates`.
+- MCP: `export_templates` and `export_offsets_pdf`, headless and connected, and a `seacraft-boatbuilding` skill
+  that has the agent ask for the skin thickness and relay every warning.
+- The DejaVu fonts moved into the core crate; PDFs embed a subset of DejaVu Sans. No change to the GUI's text.
+- Fix: cutting a hull into sections lost the last point of the first closed loop and could report a later loop as
+  open. This changes computed numbers where a section has closed loops. On the example hulls: the Wigley hull's
+  midship section area and midship coefficient rise 9.5 % (Cm 0.6066 to 0.6639; the Wigley form's own value is
+  2/3) and its prismatic coefficient falls 8.6 % (0.7286 to 0.6656, also 2/3 for the form); the demo hull's
+  section area at its transom falls 1.0 %, so `seacraft sac` gives Cp 0.7097 instead of 0.7029. Every other
+  quantity `hydro` and `sac` report for the seven example hulls moved by less than 0.01 %, and the demo-hull
+  reference numbers checked in CI did not change.
+
 ## 0.3.0 (2026-11-13)
 
 0.3.0-beta.1 with one fix:

DISCLAIMER.md

@@ -15,6 +15,11 @@ own earlier output to catch changes. [`docs/oracles.md`](docs/oracles.md) says w
 from. Passing those tests shows that the code agrees with those cases, not that its results are right
 for a real vessel.
 
+Building patterns (station moulds, profile and transom) and the printed table of offsets are geometry the
+program computed from the hull. They have not been compared with a built boat, and no printed set has been
+measured. A builder must print at 100 %, measure the printed calibration rules, and check dimensions against
+the design before cutting anything.
+
 Results can be wrong, including results that look plausible. A qualified person must check them
 independently before anyone relies on them for a design, construction, operating or safety decision.
 

NOTICE

@@ -32,11 +32,13 @@ from solidcore's crates/solidcore/src/nurbs/srf_fit.rs, licensed under the Apach
     the Apache License, Version 2.0, except where otherwise noted.
 
 Fonts
-The desktop GUI embeds DejaVu Sans and DejaVu Sans Mono 2.37, unmodified, from
-crates/seacraft-gui/assets/fonts. They are not under the GPL. Bitstream Vera Fonts: Copyright (c)
-2003 by Bitstream, Inc. All Rights Reserved. Bitstream Vera is a trademark of Bitstream, Inc. Arev
-Fonts: Copyright (c) 2006 by Tavmjong Bah. All Rights Reserved. DejaVu changes are in the public
-domain. The licence is in crates/seacraft-gui/assets/fonts/LICENSE-DejaVu.txt.
+The program embeds DejaVu Sans and DejaVu Sans Mono 2.37 from crates/seacraft-core/assets/fonts. The
+desktop GUI uses them unmodified. PDF exports embed a subset of DejaVu Sans: the glyphs the document
+uses, with the font's own name table and copyright notice. They are not under the GPL. Bitstream
+Vera Fonts: Copyright (c) 2003 by Bitstream, Inc. All Rights Reserved. Bitstream Vera is a trademark
+of Bitstream, Inc. Arev Fonts: Copyright (c) 2006 by Tavmjong Bah. All Rights Reserved. DejaVu
+changes are in the public domain. The licence is in crates/seacraft-core/assets/fonts/LICENSE-
+DejaVu.txt.
 
 Dependencies
 Dependency licences are in THIRD-PARTY-LICENSES.txt: a list in this repository, and the full texts

README.md

@@ -569,6 +569,26 @@ surfaces (entity 128) across the resampled starboard and port station curves,
 and `export::threemf` (`-o hull.3mf`) writes a welded, watertight 3MF 1.3
 archive in metres.
 
+### Building patterns
+
+`seacraft templates` cuts full-size station moulds from the refined hull, and
+optionally the profile (backbone) and a raked transom drawn true in its own
+plane. Each section is moved inward by the skin thickness (`--skin-mm`), by
+`t / cos α` where the hull meets the plane at α off square, so the outside of
+the planking lands on the designed surface; a piece of the section the skin
+consumes at a corner is dropped, as an inward offset does. Each sheet names the
+face of the mould that goes on the station line, the largest bevel and the
+longest straight piece of mesh, and can carry strongback legs, waterlines and
+the design waterline. The PDF writer is the project's own (no dependency): it
+tiles a pattern over A4, A3 or Letter with join marks, a map page and two
+100 mm check rules, or puts one pattern on each page for a plotter; SVG and DXF
+(millimetres, `CUT`/`MARK`/`REFERENCE`/`TEXT` layers) are one drawing.
+`seacraft offsets --pdf` prints the table of offsets in millimetres, with
+feet-inches-eighths beside it on `--imperial`. The desktop app has the same
+under File ▸ Builder templates…, and the MCP server as `export_templates` and
+`export_offsets_pdf`. [`docs/building.md`](docs/building.md) is the builder's
+guide.
+
 ---
 
 ## 3. Command line
@@ -583,7 +603,11 @@ seacraft sac       hull.fef [--stations N] [--csv out.csv] [--svg sac.svg] [--js
 seacraft bonjean   hull.fef [--stations N] [--drafts T1,T2,...] [--draft-steps N]
                               [--csv out.csv] [--svg bonjean.svg] [--json]
 seacraft offsets   hull.fef [--stations N] [--waterlines h1,h2,...] [--buttocks y1,y2,...]
-                              [--csv out.csv] [--html offsets.html] [--json]
+                              [--csv out.csv] [--html offsets.html] [--pdf offsets.pdf [--imperial]] [--json]
+seacraft templates hull.fef -o moulds.pdf|.svg|.dxf [--stations N | --spacing M | --at x1,x2,...]
+                              [--skin-mm MM] [--half] [--strongback Z] [--waterlines h1,h2,...]
+                              [--profile] [--transom X,RAKE] [--paper a4|a3|letter|WxH] [--single-page]
+                              [--margin-mm MM] [--overlap-mm MM] [--scale 1:N] [--imperial] [--json]
 seacraft transform hull.fef -o scaled.fef [--lwl L] [--bwl B] [--draft T]
                               [--scale sx,sy,sz] [--translate dx,dy,dz] [--mirror x|y|z] [--json]
 seacraft resistance hull.fef [--method holtrop|michell|dsyhs] [--cat-spacing S]
@@ -752,6 +776,9 @@ software. Comparing them with published data is the most useful contribution any
   and hydrostatics docks, file actions) is implemented and tested headlessly.
 * DXF export of the linesplan (2D views plus 3D curve copies) is implemented
   and audit-clean under `ezdxf`.
+* Building patterns are checked against closed-form shapes and against
+  poppler's rendering of the PDF; nobody has yet measured a printed set or built
+  on one, and the PDFs have not been opened on Windows or macOS.
 * Zebra / curvature / draft analysis and a CPU z-buffer renderer with PNG
   output are implemented, in the CLI and in all four GUI viewports. Curvature
   combs are drawn both on the linesplan (`--combs`, SVG and DXF) and in the four
@@ -773,7 +800,8 @@ software. Comparing them with published data is the most useful contribution any
   `save_hull`, `move_point`, `set_crease`, `split_face`, `insert_edge`,
   `transform_hull`, `hydro_compute`, `hydro_table`, `stability_cross_curves`,
   `bonjean_curves`, `table_of_offsets`, `unfold_plate`, `resistance_curve`,
-  `planing_curve`, `trim_scan`, `optimize_hull`, `export_linesplan` and `render_png`.
+  `planing_curve`, `trim_scan`, `optimize_hull`, `export_linesplan`, `export_templates`,
+  `export_offsets_pdf` and `render_png`.
   Agent skills that teach an AI agent to use these tools well (hull design,
   fairing, stability checks) are in [`skills/`](skills/README.md), with install
   steps and the CI test that keeps them in step with the tools.

ROADMAP.md

@@ -14,6 +14,8 @@ see [`DISCLAIMER.md`](DISCLAIMER.md).
 - Resistance by Holtrop-Mennen, Michell thin-ship theory and Savitsky; a hull optimiser.
 - Strip-theory heave and pitch motions, irregular head seas, MSI.
 - Lines plans (SVG, DXF, IGES), mesh exports (OBJ, STL, 3MF, PLY, HTML), an HTML design report.
+- Full-size building patterns: station moulds with the skin deducted, profile and raked transom, as a PDF
+  tiled over ordinary paper, one page a pattern, SVG or DXF; the table of offsets as a PDF.
 - A command line, a loopback control channel, and an MCP server for AI agents.
 
 ## Next
@@ -81,14 +83,31 @@ takes about 140 ms to build on the window thread and 12 ms to upload.
 ### M5: Binaries
 
 - [x] Replace egui's default fonts, whose `Ubuntu-Light.ttf` is under the Ubuntu Font Licence, with DejaVu
-  (`crates/seacraft-gui/assets/fonts`, `NOTICE`).
+  (`crates/seacraft-core/assets/fonts`, `NOTICE`).
 - [x] Ship full licence texts with binaries: `cargo xtask dist` writes them from the crates that are compiled in.
 - [x] Add release packaging: a version tag builds a Linux archive, AppImage and Flatpak bundle, a Windows zip
   and macOS disk images, then creates a draft release (`.github/workflows/release.yml`, `packaging/`).
 - [ ] Make the first release: run the workflow, and have someone open the GUI on Windows and on a Mac.
 - [x] Decide on publishing to crates.io: not now. The people a release is for download a program, and the
   library API is not meant to be stable yet. Flathub waits too, since it must build from source.
 
+### M6: Builder's toolkit
+
+- [x] Station moulds from the refined hull, with the skin deducted along the surface normal, mould face and
+  bevel on each sheet, strongback legs, half moulds (`crates/seacraft-core/src/templates.rs`).
+- [x] Profile (backbone) and raked transom patterns.
+- [x] A dependency-free PDF writer with an embedded DejaVu subset, tiled over A4, A3 or Letter with join marks,
+  a map page and 100 mm check rules, or one page a pattern; SVG and DXF in millimetres (`sheet.rs`, `pdf.rs`).
+- [x] The table of offsets as a PDF, metric with feet-inches-eighths beside it.
+- [x] The same in the CLI (`seacraft templates`, `offsets --pdf`), the GUI (File ▸ Builder templates…), the
+  control channel (`build.templates`) and MCP (`export_templates`, `export_offsets_pdf`), with a boatbuilding
+  skill.
+- [ ] Print the calibration page and one station and measure them.
+- [ ] Open the PDFs on Windows and macOS viewers.
+- [ ] Plywood panels: developed shapes of hull panels for stitch-and-glue, with their joins.
+- [ ] Materials and weight: skin area, plywood sheets, glass and resin, and the weight they add.
+- [ ] A build pack: patterns, offsets, panels and a cutting list in one document.
+
 ## Gap review
 
 | Area | Today | Missing |