JumpStart 3D v2.3 (community build 21)

Based on JumpStart 3D by J.Siwek, version 2.3, https://classyapps.org/, plus the community additions. Use it online at https://maxsikorski.github.io/jumpstart-3d/ or download jumpstart-3d.html below and open it in any modern browser.

A fourth mode for houses and buildings: Architechies

From J.Siwek's v2.2. Architechies is a mode for drawing buildings: floor plans, walls, doors and windows, roofs and levels. When the building is ready, Send to design brings it into a normal design so you can keep working on it.

Toolpaths and G-code: CAM Studio

From J.Siwek's v2.3. In Advanced, under Simulate, CAM Studio builds toolpaths, previews the material being cut away, and writes G-code for GRBL, LinuxCNC, Mach3 and Marlin. It can also stream the code to a machine over USB; the browser asks for permission first. Five new tutorials come with it, 44 in all.

Report a problem

Under the menu and in About, Report a problem opens a GitHub bug report with your app details already filled in: the build, the mode and the last error. Nothing is sent until you press Create on GitHub. Personal folder paths and names are cleaned out first, and the cleaner now catches more of them.

See your design from underneath

Look at a design from below the build plate and the plate turns nearly clear, so you can see the underside of the part. From above nothing changes. Thanks to branttheconstraint for the report (issue #96).

Boolean fixes

• A torus no longer disappears after Group, Join, Cut or Intersect.
• Sphere intersections and cuts give the right volume.
• When nothing is left, the app says "Nothing is left" instead of showing an error code.

Designs open framed

Re-opening a design frames the view straight away, and the camera no longer jumps back after your next edit.

Behind the scenes

A fuzzer runs random but repeatable chains of operations through the real buttons and checks the result after every step. All 44 tutorials are walked automatically on both builds, so a new button without a tutorial fails the tests. The test run on each change is about five minutes instead of about half an hour. An upstream merge tool lists what needs a human when J.Siwek publishes a new version, and the chat judge runs nightly.

Also in this build

Everything from build 20: cut bodies that split into two, the review gate, the About changes and all earlier additions.

Files

• jumpstart-3d.html: the app as one file. Download and open it; no install needed.
• Online: https://maxsikorski.github.io/jumpstart-3d/

The untouched upstream v2.3 file and the author's source zip are on the upstream-originals release.

JumpStart 3D v2.1.3 (community build 20)

Upstream JumpStart 3D by J.Siwek (his site: https://classyapps.org), version 2.1.3, plus the community additions. Use it online at https://maxsikorski.github.io/jumpstart-3d/ or download jumpstart-3d.html below and open it in any modern browser.

Cutting a body in two now gives two bodies

Reported on Reddit: cutting through an object with Combine sometimes left both halves "stuck" as one object. Now, when Combine (Advanced) or Hole + Group (Beginner) cuts a body fully in two, each piece becomes its own body, with the same colour, so you can select and move them separately. One undo puts it back. A cut that does not go all the way through still leaves one body, and groups of shapes that never touched, or text, stay grouped. Editing a cut later so it goes through splits it too.

A design saved with split pieces needs build 20 or newer to open.

Review gate

Every change to the community build now goes through written review rules (REVIEW.md): the requester's end result tested first, two independent AI reviews, CI with the export judge and the phone budget, and a check after release. Bug reports and feature requests on GitHub now ask "What should it end up as?".

About

About now leads with Visit the community build and Support, with J.Siwek's site right beside them; the "Created by J.Siwek" credit is unchanged.

Also in this build

Everything from build 19: J.Siwek's v2.1.3 (Pattern on face, Voxel Studio, 20 tutorials, 26 textures), OBJ import, install as an app, Your server previews, cleaner STL files, and all earlier community additions.

Files

• jumpstart-3d.html: the app as one file. Download and open it; no install needed.
• Online: https://maxsikorski.github.io/jumpstart-3d/

The untouched upstream files and the author's source zips are on the upstream-originals release.

JumpStart 3D v2.1.3 (community build 19)

Upstream JumpStart 3D by J.Siwek (his site: https://classyapps.org), version 2.1.3, plus the community additions. Use it online at https://maxsikorski.github.io/jumpstart-3d/ or download jumpstart-3d.html below and open it in any modern browser.

J.Siwek's v2.1.3

The author's latest release, merged in full:

• Pattern on face (Beginner toolbar › Face pattern; Advanced › Decorate › Pattern on face): raise or cut hexagons, diamond plate, screen mesh, circles, triangles, knurl or ribs on a flat face, as an editable feature.
• Voxel Studio (Advanced › Simulate): turn objects into cubes you can paint face by face, add and remove, then export as STL or colored 3MF or add back to the design.
• 20 more tutorials, from Easy to a new Expert level (39 in all, with the community Parameters tutorial).
• 26 new textures in Wood, Building and Fabric groups.
• Easier text: 3D text that lies on any face, and dragging with snapping for embossed and sketch text.
• Arrow keys move parts the way they look on screen, whatever the camera angle; , and . turn by 1°.

OBJ import

Tinkercad and many other tools export OBJ. Beginner's Import button and Advanced › Insert › STL / OBJ / 3MF / STEP model now read it, repaired on the way in like STL. OBJ comes in as millimetres.

Install it as an app

Chrome and Edge show an Install button for the site, and Safari's File › Add to Dock uses the right name and icon: its own window and Dock icon, working offline.

Also new

• Your server (self-hosted WebDAV storage) shows design previews, like This browser.
• Cleaner STL files: exports no longer contain zero-area triangles; every export in the test suite is now checked by PrusaSlicer and FreeCAD.
• About › Check for updates asks the community releases, only when you click it. About and the splash show the version as 2.1.3 · community build 19.

Also in this build

Everything from earlier builds: Your server (WebDAV) storage, Name plate, Gear, Hole pattern and Fastener dialogs, designs in the browser's larger storage with folder copies, restore and backups, the chat panel, the workspace that opens at once, the site that works offline, and the AI-agent connection (MCP server unchanged at 0.2.8).

Files

• jumpstart-3d.html: the app as one file (15,322,407 bytes, SHA-256 0b4469ec43e72a97d9f92430c575edb761fcfdf406a036935b41c81c9c6bced6). Download and open it; no install needed.
• Online: https://maxsikorski.github.io/jumpstart-3d/

The untouched upstream 2.1.3 file and the author's source zip are on the upstream-originals release.

JumpStart 3D v2.0 (community build 9)

Upstream JumpStart 3D by J.Siwek (his source repository), version 2.0, plus the community additions. Use it online at https://maxsikorski.github.io/jumpstart-3d/ or download jumpstart-3d.html below and open it in any modern browser.

The workspace opens at once

The website no longer makes you wait at a splash screen. The workspace is ready in about 2 seconds on a 10 Mbit connection, instead of about 10. The geometry engine (7 MB) downloads in the background, a small note in the corner of the 3D view shows how far it has got, and shapes you add appear when it is ready. A STEP export that a restart of the geometry engine interrupts now reports it instead of hanging.

Fast after the first visit

After that first visit the site keeps a copy on your computer, so it opens in well under a second and works without an internet connection (only the fonts come from the web). When a new version is published it downloads in the background and a message asks you to reload. The downloaded single file is unchanged.

The tab icon shows everywhere

The icon from build 8 did not show in Safari or in a private Brave window. It is now served as real image files, so every browser shows it, and iPhones and iPads get a home-screen icon when the site is added there.

What to check

Safari and Brave users: the tab icon should now appear; tell me if it does not.

Also in this build

Everything from build 8: back up and restore all your designs, and the logo in the tab. Everything from build 7: the chat panel inside the app, the scripting bridge, Run script…, and the MCP server with its Claude Code plugin, skill and command line. The MCP server is now 0.2.3: its headless browser no longer keeps a stored copy of the site, and .svg files are served with the right type. For anyone curious, tools/measure-load.mjs measures how fast the site loads on a slow connection.

Files

• jumpstart-3d.html: the app as one file. Download and open it; no install needed.

The untouched upstream 2.0 file and the author's source zip are on the upstream-originals release.

JumpStart 3D v2.0 (community build 8)

Upstream JumpStart 3D by J.Siwek, version 2.0, plus the community additions. Use it online at https://maxsikorski.github.io/jumpstart-3d/ or download jumpstart-3d.html below and open it in any modern browser.

Back up and restore all your designs

Designs live in your browser's storage, which "clear site data" wipes. In Your designs there are now two buttons: Back up all designs… saves every design in this browser into one file, and Restore from backup… puts them back, on this or another computer. Restore only adds: a design that is not there is added, an identical one is left alone, a changed one is kept next to a "(restored)" copy. Nothing is ever deleted or overwritten, and the design you have open is never touched. If the browser runs out of room part-way, the file tells you what did not fit and leaves nothing half-done.

The logo in the tab

The three-layer logo from the loading screen is now the browser tab icon (website and single file) and sits in the corner of the link-preview card.

Also in this build

Everything from build 7: the chat panel inside the app (Ollama, LM Studio, OpenAI-style services, Anthropic), the JS3D scripting bridge, Run script…, and the MCP server with its Claude Code plugin, skill and command line.

Files

• jumpstart-3d.html: the app as one file. Download and open it; no install needed.

The untouched upstream 2.0 file and the author's source zip are on the upstream-originals release.

JumpStart 3D v2.0 (community build 7)

Upstream JumpStart 3D by J.Siwek, version 2.0, plus the community additions. Use it online at https://maxsikorski.github.io/jumpstart-3d/ or download jumpstart-3d.html below and open it in any modern browser.

Chat with an AI model inside the app

Build 7 puts the AI in the app itself. Click the new AI button in the top bar, pick a model, type what you want ("a 40 by 30 by 20 block with an 8 mm hole through it") and watch the design change. Nothing to install, no agent session, no server: the page talks to the model directly and edits the design through the same 34 tools the MCP server has. Every step shows in the chat, and each one is an ordinary undo step.

Four kinds of model:

• Ollama on your computer (http://localhost:11434): free, offline, no key. Pick a model that supports tools; 9B or larger works best, and one with vision can look at screenshots.
• LM Studio on your computer (http://localhost:1234/v1): same, no key.
• Any OpenAI-style address with a key: OpenAI, OpenRouter, Groq, oMLX and the like.
• Anthropic with a key (Claude Sonnet 5.5 is the default).

A local server has to allow the page to talk to it, once. Ollama needs OLLAMA_ORIGINS="*" before it starts; the panel shows the exact line for macOS, Linux and Windows when it cannot reach the server. LM Studio needs Enable CORS in its server settings. The single file needs the same.

What stays where: your key stays in this browser and is saved only if you tick Remember key. Nothing is sent until you press Send. The model can only use the tools; Allow scripts is off unless you tick it. There is no default hosted provider and no telemetry.

Also in this build

Everything from builds 4 to 6: the JS3D scripting bridge, Open/Export › Run script…, and the MCP server with its Claude Code plugin, skill, command line and one-line setup for other agents. The MCP route stays for agents that live outside the browser; the chat is for everyone else. The plugin is now 0.2.1: claude plugin update jumpstart-3d@maxsikorski.

For people who change the code

Three new modules (src/chat.js the panel and the loop, src/chattools.js the 34 tools as direct JS3D calls, src/chatproviders.js the adapters), one button and one panel in src/index.html, two lines in app.js. A node test keeps the chat's tool list identical to the server's (names, descriptions and parameters, except six documented differences). test/chat.spec.mjs drives the panel on both builds against a mock model server that speaks the Ollama, OpenAI and Anthropic shapes.

Files

• jumpstart-3d.html: the app as one file. Download and open it; no install needed. The chat works from the file too (a local server needs the setting above).

The untouched upstream 2.0 file and the author's source zip are on the upstream-originals release.

JumpStart 3D v2.0 (community build 18)

Upstream JumpStart 3D by J.Siwek (his source repository), version 2.0, plus the community additions. Use it online at https://maxsikorski.github.io/jumpstart-3d/ or download jumpstart-3d.html below and open it in any modern browser.

Your designs on your own server (WebDAV)

Your designs now has two tabs. This browser is everything that was there before. Your server lists, opens, saves and deletes designs on your own WebDAV server, such as a NAS (TrueNAS, Nextcloud, Synology), or an Apache or nginx folder set up for WebDAV. Designs are stored as the same project files the folder copies use, so you can switch devices, including an iPad. Safari works there; it has no folder picker, so this is the way to get designs off an iPad.

Type the server address and sign in once per browser. The Test connection button says exactly what is wrong: a plain-http server behind an https page, a blocked cross-origin request, a wrong password, or a wrong folder (with a Create the folder button).

The simplest route needs no server-side setup: put the app page inside the WebDAV share itself, with a designs/ folder next to it (or a storage.json file that names the folder). That avoids the cross-origin setup entirely. The README section "Setting up your server" has the steps for TrueNAS (CORE 13's WebDAV service; SCALE needs an app since 23.10), Nextcloud, Apache and nginx.

For contributors: two judges in CI

Two of the project's automatic judges now run in CI. Every test run walks a first part on a simulated phone (a box with a hole, grouped, exported as STL) over a slow 4G connection, and fails if it takes longer than its budget. A geometry-scored chat benchmark (50 plain-language requests, each with the expected volume, box and hole count) runs five scripted cases on every test run, and can score a real local model on demand with npm run chat-bench and Ollama. Nothing changes for users; it keeps the app honest.

For AI agents

The MCP server is unchanged at version 0.2.8, so nothing needs updating for agents this build.

Also in this build

The Name plate… dialog from build 17 (raised or cut-in text on a plate, with no hole, a hanging hole or two screw holes), the Gear… dialog from build 16, the Hole pattern… dialog from builds 14 and 15, the square, hex and slot holes from build 15, everything from builds 10 to 13 (your designs in the browser's larger storage, copies of your designs into a folder, restore from a folder, and the Fastener dialog for bolts, nuts, rods and tap cutters) and earlier: the chat panel inside the app, back up and restore of all your designs, the workspace that opens at once, the site that works offline, and the tab icon in every browser. Build 17's test-harness fix (no app change) that stops a rare extra reload on the CI runner is included too.

Files

• jumpstart-3d.html: the app as one file (15,196,192 bytes, SHA-256 2de2c61af46231fccf5183dc18ea857914f047966496ee4e84c33b9d770ed63d). Download and open it; no install needed.
• Online: https://maxsikorski.github.io/jumpstart-3d/

The untouched upstream 2.0 file and the author's source zip are on the upstream-originals release.

JumpStart 3D v2.0 (community build 17)

Upstream JumpStart 3D by J.Siwek (his source repository), version 2.0, plus the community additions. Use it online at https://maxsikorski.github.io/jumpstart-3d/ or download jumpstart-3d.html below and open it in any modern browser.

Name plates: raised or cut-in text on a plate

The new Name plate… dialog sits under Advanced Create, next to Gear, and a Name plate button is in the Beginner toolbar. Type the words, pick one of the three bundled fonts, and set the size and the height. The dialog makes a plate sized to the text with a margin: a rounded rectangle or a pill, with no hole, a hanging hole or two screw holes.

The text is either raised, as a second body in its own colour, or cut into the plate. Raised text gives a 3MF with two colours: change filament at the plate's top, or let a multi-colour printer read them. Cut-in text keeps the plate one colour. Either way the whole plate is one undo step.

The words can be edited later: raised text in Beginner's inspector, cut-in text in the Emboss dialog. The plate does not resize afterwards. The dialog refuses plainly when the text has a second line, runs past 40 characters, uses characters the fonts do not have (it lists them), or is too small for a hole.

For AI agents

The MCP server is version 0.2.8 and has 38 tools. The new tool add_name_plate takes the text, the font, the size and height, whether the text is raised or cut in, the plate shape, the margin, the holes, the colours and the position. The browser bridge gets JS3D.namePlate (bridge 1.6). To update the plugin, run claude plugin update jumpstart-3d@maxsikorski.

Also in this build

The Gear… dialog from build 16, the Hole pattern… dialog from builds 14 and 15, the square, hex and slot holes from build 15, everything from builds 10 to 13 (your designs in the browser's larger storage, copies of your designs into a folder, restore from a folder, and the Fastener dialog for bolts, nuts, rods and tap cutters) and earlier: the chat panel inside the app, back up and restore of all your designs, the workspace that opens at once, the site that works offline, and the tab icon in every browser. This build also has a test-harness fix (no app change) that stops a rare extra reload on the CI runner.

Files

• jumpstart-3d.html: the app as one file (15,179,805 bytes, SHA-256 47e9d78695d5e79a7fe06323d2c8dfe16a15655663f17b4c5ef3bf706f754dd0). Download and open it; no install needed.
• Online: https://maxsikorski.github.io/jumpstart-3d/

The untouched upstream 2.0 file and the author's source zip are on the upstream-originals release.

JumpStart 3D v2.0 (community build 16)

Upstream JumpStart 3D by J.Siwek (his source repository), version 2.0, plus the community additions. Use it online at https://maxsikorski.github.io/jumpstart-3d/ or download jumpstart-3d.html below and open it in any modern browser.

Gears from a dialog: spur, rack and bevel

The new Gear… dialog sits under Advanced Create, next to Fastener, and a Gear button is in the Beginner toolbar. Pick spur gear, rack or bevel gear. For all three you set the module (tooth size, metric; when inch units are on, the inch "diametral pitch" is shown instead), the number of teeth and the face width. A spur gear can also take an optional bore with a standard (DIN 6885) keyway.

The teeth are a true involute with a 20° pressure angle and standard proportions. A small print clearance (0.1 mm by default) makes printed pairs run freely. A gear is an ordinary body, so it fillets, shells and exports as clean STEP like anything else. It is built from a sketch and an extrude (bevel: two sketches and a loft), so you can edit it later in the timeline.

Pairing: two spur gears mesh when their centres are module × (teeth1 + teeth2) / 2 apart and the second gear is turned half a tooth. The bevel gear is made for a 90° pair and is an approximation (a scaled tooth), and the docs say so.

Limits: gears from 12 teeth are allowed with a warning, since there is no undercut correction. Spur gears go up to 200 teeth (about 3 seconds to build), bevel gears up to 90, and the sketch editor gets slow above 120 teeth. Helical gears are not in this build: the only twist the engine offers gives wrong teeth without any warning once the twist is more than small, so they wait for a proper method.

For AI agents

The MCP server is version 0.2.7 and has 37 tools. The new tool add_gear takes kind (spur, rack or bevel), module, teeth, width, bore, keyway, clearance and position. The browser bridge gets JS3D.gear (bridge 1.5). To update the plugin, run claude plugin update jumpstart-3d@maxsikorski.

Also in this build

The square, hex and slot holes from build 15, the Hole pattern… dialog from build 14 (round holes in rows, staggered rows or a circle, as plain, counterbore, countersink or tapped holes, all in one go), everything from builds 10 to 13 (your designs in the browser's larger storage, copies of your designs into a folder, restore from a folder, and the Fastener dialog for bolts, nuts, rods and tap cutters) and earlier: the chat panel inside the app, back up and restore of all your designs, the workspace that opens at once, the site that works offline, and the tab icon in every browser.

Files

• jumpstart-3d.html: the app as one file (15,168,017 bytes, SHA-256 3086c79885496e6da41d767ca2658e8b07c250e3cabe319ff5c1d35477831bcf). Download and open it; no install needed.
• Online: https://maxsikorski.github.io/jumpstart-3d/

The untouched upstream 2.0 file and the author's source zip are on the upstream-originals release.

JumpStart 3D v2.0 (community build 15)

Upstream JumpStart 3D by J.Siwek (his source repository), version 2.0, plus the community additions. Use it online at https://maxsikorski.github.io/jumpstart-3d/ or download jumpstart-3d.html below and open it in any modern browser.

Square, hex and slot holes in the Hole pattern dialog

The Hole pattern… dialog has a new Shape field. Round is as before; square, hex and slot are new. The same layouts apply: a grid with a set spacing or fitted to the face, staggered rows, an angle, or a circle, with the same edge margin. Shapes that would not fit the face are left out. The fit is now measured from each shape's real outline rather than a circle around it, so a thin vent slot fits a narrow face.

Sizes: square takes a side; hex takes the distance across the flats (the flats face the columns, so a staggered grid with the row spacing at 0.866 times the column spacing makes a honeycomb); slot takes a width and a length, with the length along the columns, or pointing at the centre on a circle.

Round holes are still one ordinary Hole feature. Square, hex and slot patterns are written as one hidden sketch on the face, with every outline, plus one Extrude cut on that body, all in one undo step. The timeline shows the sketch (named like "Hex holes (24)") and the cut, and you edit the cut in the Extrude dialog. Overlapping outlines are refused when you press Create. A pattern is limited to 200 shapes (200 hexagons build in about 7 seconds on a laptop), and the dialog warns above 100. Good for nut traps, vents and pegboard slots.

One thing to know: the cut goes down to the body's depth below the face plus 1 mm. If you later make the body taller on that side, the cut still starts at the old face.

For AI agents

The MCP server is version 0.2.6 and still has 36 tools. The tool add_hole_pattern gains shape, width and length. The browser bridge's JS3D.holePattern takes hole.shape, hole.width and hole.length (bridge 1.4). To update the plugin, run claude plugin update jumpstart-3d@maxsikorski.

Also in this build

The Hole pattern… dialog from build 14 (round holes in rows, staggered rows or a circle, as plain, counterbore, countersink or tapped holes, all in one go), everything from builds 10 to 13 (your designs in the browser's larger storage, copies of your designs into a folder, restore from a folder, and the Fastener dialog for bolts, nuts, rods and tap cutters) and earlier: the chat panel inside the app, back up and restore of all your designs, the workspace that opens at once, the site that works offline, and the tab icon in every browser.

Files

• jumpstart-3d.html: the app as one file (15,156,843 bytes, SHA-256 842e4b1a75b9af724ab24cb365f84a410fde7c94f739ca786129e732ad5a4ad0). Download and open it; no install needed.
• Online: https://maxsikorski.github.io/jumpstart-3d/

The untouched upstream 2.0 file and the author's source zip are on the upstream-originals release.