The sample and the evidence are free. The book and the instrument are licensed.
A platform whose claim is that its figures close has to let people check the proof. So the evidence sits outside the paywall permanently: the source index, the measured residuals, the library of published figures, the colour records — and Part I of the book with the verse chapter, so the argument can be read before it is bought.
What a licence buys is the work itself: the complete book — the same text as the printed edition — and the studio, where figures are made: five parameters, every condition, every named figure, the animated construction, and exports from SVG to CAD to a carvable solid.
The sample and the evidence, free. Part I of the book, the annotated sources, the library of published figures with their residuals, and the colour evidence. The complete book and the instrument are licensed.
The studio, unlocked — every parameter, condition and named figure — with print-ready files at any size your printer will take.
For making things. CAD and every three-dimensional format, the stacking plates, and a licence to sell what you make.
For temples, museums, universities and manufacturers. Everything, plus the API and named support.
Licences are monthly and cancel any time from the billing page; the figures you have already downloaded remain yours to use under the licence they were made with.
| format | what it is for | included from |
|---|---|---|
| SVG | Vector, resolution-independent, with named layers. Opens in Illustrator, Inkscape, Figma and Affinity. Also the source for the raster exports. | Practitioner |
| Print-ready vector, with optional bleed, crop marks and a certificate page. | Practitioner | |
| DXF | For laser cutters, CNC routers, engravers and CAD. Geometry only, one DXF layer per element group. | Workshop |
| STL — text | The Meru as a closed mesh. Universally readable, but large and unitless; the slicer has to be told these are millimetres. | Workshop |
| STL — binary | The same solid at about a fifth the size. Prefer this unless something refuses to open it. | Workshop |
| 3MF | What modern slicers want — PrusaSlicer, Bambu, Orca, Cura. Carries its units, so it lands on the plate at the size you asked for. | Workshop |
| glTF / GLB | For the web and for game engines: three.js, Babylon, Godot, Unity, Blender. Flat-shaded, because the Meru is a stepped solid. | Workshop |
| OBJ | The Meru for Blender, Maya and anything that will not take the others. | Workshop |
| PLY | Indexed and compact, for MeshLab, CloudCompare and Open3D — if you mean to process the mesh rather than print it. | Workshop |
| AMF | The ISO alternative to STL. Carries units and colour. | Workshop |
| Stacking plates — SVG | The Meru as nine flat plates nested on one sheet, with the thickness of each printed beside it. Cut the black, engrave the grey, stack in order. | Workshop |
| Stacking plates — DXF | The same nine plates for a laser or router, one layer per plate, cut and score separated. | Workshop |
| JSON | Every coordinate, every intermediate, the residuals and the certificate. | Practitioner |
| CSV | The nine triangles as a table, in millimetres. | Practitioner |
| Construction table | The nine horizontal lines and half-widths, for drawing by hand. | Practitioner |
| Polylines | Raw polylines by layer, for writing your own exporter. | Practitioner |
| Kūrma SVG | The spherical form as vector line work, in your choice of projection. Free, because Part VI is the least-corroborated part of this work and its only picture should not sit behind a paywall. | Practitioner |
| Kūrma PDF | Print-ready vector of the spherical form, with the certificate page. | Practitioner |
| Kūrma DXF | The spherical form for CAD and cutting. Note that this is the projection, not the curved surface — a domed plate needs the drawing wrapped onto it. | Workshop |
| Kūrma plate STL | The domed plate itself — the figure incised into a spherical cap, watertight and printable. Not the flat drawing: cutting that out and bending it would put every line in the wrong place. | Workshop |
| Kūrma plate glTF | The same solid, for viewers and rendering. | Workshop |
| Kūrma plate 3MF | The same solid, with units carried in the file, for slicers that honour them. | Workshop |
| Kūrma data | Six parameters, derived arcs, both residuals, the cap proportions, and the minimum cap radius below which the figure does not exist. | Practitioner |
| PNG / WebP / JPEG | Raster, rendered in your browser from the SVG. Resolution is what the tier allows. | Practitioner |
Worth stating, because a paywall whose gaps only the seller understands is not an honest one. SVG is vector: any licensed tier that receives one can rasterise it at any resolution or scale it to any size with tools it already has, so the dpi and size ceilings bound what this application will do — which covers most people — rather than what a determined person could. What is genuinely enforced is the format set: the CAD and mesh files are generated on the server and are never sent to a tier that has not licensed them, and the free tier receives no files at all.
Enforcement is server-side throughout — 4 tiers, every format mapped, every limit checked in the export route itself. The tier is read from a signed entitlement on the server and never from the request, so a client cannot obtain a format by asking nicely.