Ribcast STL Sections

Ribcast extracts planar cross sections from an existing STL model and creates real vector files. For makers and model designers who need a quick mobile section reference, outline handoff or contour inspection.

FROM MODEL TO SECTIONS Import a binary or ASCII STL from Files. Confirm whether one source unit means one millimeter or one inch: STL files have no unit metadata. Choose the X, Y or Z section axis, choose 1–24 evenly spaced sections or name exact nonuniform positions in mm from the STL coordinate origin. Edit each station name and position, add/remove stations, and preserve your chosen order. Out-of-range, overlapping and non-finite positions are rejected before replacing the saved plan.

INSPECT THE REAL GEOMETRY Orbit and zoom the source model while the selected plane follows your section. Browse the contour strip, compare projected width and height, and see closed contours, open contours, branch nodes and skipped coplanar triangles. On iPad, the source and section workspace sit side by side.

KEEP A REPEATABLE SETUP Save up to 12 models with local original files, names, notes and section settings. Reopen, rename or delete models and their local outputs. Save and remove up to 20 reusable setup presets. A fresh install starts empty; an optional original ribbed-vessel sample runs through the same STL parser and section engine.

EXPORT ACTUAL FILES Build one ZIP with an SVG and DXF for every section, a fitted section-book PDF, coordinate CSV, section-summary CSV, Project.json settings, the original STL, its SHA-256, a complete source + plan JSON backup and a Readme. Preview the actual PDF and share the ZIP with the native share sheet.

SVG and DXF use millimeters; DXF sets its unit header to mm. Coordinates retain the source projected axes. SVG applies a Y flip for display. Vector and CSV coordinates round to 0.001 mm. PDF views fit each page and print their scale; they are not automatically full-size cutting templates. Verify units and scaling in the receiving app and printer.

One upfront purchase includes all features. No subscription, in-app purchases, account, advertising, analytics, tracking, developer upload or network service. Device backups follow system settings. Keep original files separately.

SCOPE AND LIMITS Up to 15 MiB and 100,000 triangles per STL, 24 sections and 300,000 total section points. Up to 200 MiB of saved source files. Available device space is required. Coordinates must be finite and within supported bounds.

Open paths remain open. Branch nodes split paths. Coplanar triangles are skipped and counted; tangent or boundary sections may be incomplete. Ribcast does not repair or certify mesh topology, infer wall thickness or printability, edit solids, nest shapes, compensate kerf, generate toolpaths or G-code, connect to printers or guarantee manufacturing results. Inspect outputs in the destination application before use.

The ZIP includes model names, notes and the original STL; review it before sharing. Project.json documents the chosen setup; import Source-Plan.ribcast.json through + to restore source, names, notes and settings as a separate model after hash, format and plan checks. The ZIP itself is not imported. Backup JSON is limited to 24 MiB. Only import models you have permission to use.

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