Shell Rolling Master

Precision flat-pattern development for cylindrical and conical plate shells.

Shell Rolling Master is a browser-based fabrication calculator for rolling plate into open-seam cylindrical and conical shells. It computes neutral-fibre developments with K-factor compensation, visualizes the rolled solid and unfolded blank, and exports shop-ready DXF, PDF, and STEP deliverables — entirely client-side.

Live App · Documentation · Calculations · Architecture

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Capabilities

Area	What you get
Geometry modes	Cylinder and frustum (cone) shells with OD or ID specification
Neutral fibre	K-factor–based development along the bending neutral axis
Seam control	Configurable weld / seam gap deducted from the developed blank
Roll guides	Optional equally spaced bend / roll reference lines
3D preview	Interactive thick-shell model (orbit, pan, zoom, view cube)
2D pattern	Dimensioned SVG layout — rectangle (cylinder) or annular sector (cone)
Exports	DXF cut pattern, PDF fabrication report, STEP solid (OpenCascade WASM)
Embedding	Same-origin share-state protocol for host utility shells

All units are millimetres. Computation and CAD export run in the browser; no backend is required.

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Quick start

npm install
npm run dev

Open http://localhost:3000. Production build:

npm run build
npm run preview

Script	Purpose
npm run dev	Vite development server (port 3000, host 0.0.0.0)
npm run build	Type-checked production bundle to dist/
npm run preview	Serve the production build locally
npm run lint	ESLint across the project

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How it works

Inputs (OD/ID, D1/D2, H, T, K, gap)
        │
        ▼
 Neutral diameters  →  Cylinder / cone development math
        │
        ├──► Results card (sheet size, sector radii & angle)
        ├──► 2D SVG pattern view
        ├──► 3D Three.js thick-shell mesh
        └──► Exports: PDF · DXF · STEP (CAD worker)

1. Enter shell dimensions and material parameters.
2. The engine derives neutral diameters, then develops the flat blank (rectangle or annular sector).
3. Inspect the 3D model or 2D pattern.
4. Download PDF (shop report), DXF (CNC / CAD blank), or STEP (thick open-seam solid).

Detailed formulas: docs/calculations.md.

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Default parameters

Parameter	Default	Description
Mode	Cylinder	cylinder or cone
Spec	OD	Outer or inner diameter basis
D1	2000 mm	Primary / top diameter
D2	1500 mm	Bottom diameter (cone)
H	2500 mm	Axial height / blank width
Thickness	15 mm	Plate thickness
K-factor	0.44	Neutral-axis position (0–1)
Gap	2 mm	Weld / seam opening

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Technology

• UI: React 19 · TypeScript 5.9 · Vite 7 · Tailwind CSS 3 · Zustand 5
• 3D: Three.js · React Three Fiber · Drei
• CAD / STEP: replicad · OpenCascade.js (WASM) in a module Web Worker
• Reports: jsPDF

Relative asset paths (base: './') support static hosting and iframe embedding.

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Documentation

Document	Contents
Documentation index	Full documentation map
User guide	Inputs, workflow, validation
Calculation reference	Neutral fibre, cylinder & cone maths
Domain model	Parameters, results, types
Architecture	Modules, data flow, CAD pipeline
Export formats	PDF, DXF, STEP, share protocol
Development	Setup, build, deploy, conventions

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Project layout

src/
  App.tsx                      Layout: sidebar + 2D/3D workspace
  store/useShellStore.ts       Zustand store & recalculation trigger
  features/calculator/         Inputs, results, math, STEP export UI
  features/viewer-2d/          SVG flat-pattern views
  features/viewer-3d/          Three.js scene & shell meshes
  cad/                         OpenCascade / replicad STEP pipeline
  utils/                       DXF, PDF, bend lines, solid geometry
  shareLink.ts                 Embedded host share-state protocol

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Deployment

Pushes to main build with Node 22 and publish dist/ (as app.html) to the CAD Auto Script site under:

static/utility-apps/cylindrical-shell-rolling

See docs/development.md.

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Scope notes

• Client-side only — no project persistence, accounts, or server API.
• No laser / plasma / waterjet kerf compensation; cone reported sheet size includes a 10 mm cutting margin on the bounding box (not on DXF geometry).
• Cone mode requires a meaningful diameter difference (≥ 1 mm at neutral); near-cylindrical cases should use cylinder mode.
• STEP export initializes an OpenCascade WASM kernel on first use (progress is shown in the UI).

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License & attribution

Private project (package.json: "private": true). Part of the CAD Auto Script utility suite.

Version: 0.21.0