Plannr

Try it: plannr.m-dm.org · ☕ Buy me a coffee on Ko-fi

A SketchUp-style 3D modeller as a web app. A Rust engine owns the model and every modelling operation; the browser is a viewport with the familiar tool set; and the same operations are exposed over MCP, so an AI can draw, push/pull, move, measure, paint, annotate, change the camera and take screenshots of what it made. The core is generic — domain tools (houses, rooms, pipes…) come as plugins.

crates/plannr-core     document model, ops kernel (draw / push-pull / offset / move / rotate / scale / …), undo history,
                       tessellation + section cuts, metrics, GLB export, plugin trait
crates/plannr-server   Axum REST API + WebSocket + MCP endpoint + SQLite + static hosting (port 8795)
web/                   Vite + TypeScript + three.js frontend (SketchUp-style UI)
docs/CONTRACT.md       the document / ops / REST / WebSocket / MCP contract
docs/PLUGINS.md        how to write engine and browser plugins, and how installable packages work

A look inside

Isolate a storey for a dollhouse view: cavity walls, beam-and-block floors and the material takeoff in Model Info.	Every timber roof type, framed on the same shed by the framing plugin.
The situation plan the electrical plugin draws: points as IEC symbols, numbered per circuit, conduits dashed.	The same model in the light theme.

Public instance mode

PLANNR_PUBLIC=1 runs Plannr as a public site (this is how plannr.m-dm.org runs): the front page (web/home.html) is served at / and the modeller at /app; every browser gets a random owner key (kept in localStorage, sent as X-Plannr-Owner) and only ever sees the projects it made (at most 30); the MCP endpoint is off, and installing or switching plugins needs the server's PLANNR_TOKEN. Without it, Plannr is a single-user local app with MCP.

Run

cd web && npm install && npm run build && cd ..   # builds web/dist
cargo run --release -p plannr-server              # http://localhost:8795

The server prints an MCP token at startup (or set PLANNR_TOKEN). In the app, Help → Connect an AI (MCP)… opens a panel that stays open: it shows the endpoint and the running server's token (when the browser is on the same machine), lets you test it, and hands you the command below and a JSON config for other MCP clients with the token filled in. Connect Claude Code with:

claude mcp add --transport http plannr http://localhost:8795/mcp --header "Authorization: Bearer <token>"

Frontend development: keep the server running and use cd web && npm run dev (Vite proxies /api). Tests: cargo test. Type-check: cd web && npx tsc --noEmit.

Tools

Tool	Key	Notes
Select	Space	Shift adds, Ctrl toggles, drag a window (left→right) or crossing box (right→left), double-click enters a group or opens a plugin object (a construction wall or roof: select one face; a framed wall: single studs and plates), Esc leaves
Eraser	E	Click or drag over edges, faces, objects
Line	L	Chained edges; a closed coplanar loop becomes a face. Type a length.
Rectangle	R	Two corners on the ground or on any face; type w;h
Rotated Rectangle	—	First edge with two clicks, then the width: a rectangle at any angle in the plane
Circle	C	Centre + radius; type 24s for the number of sides
Polygon	N	Click corners, Enter closes
Arc / Pie	A	Centre, start, end (type a radius, then an angle); Pie closes the sector into a face
3 Point Arc	—	Start, a point on the arc, end
2 Point Arc	—	Both chord ends, then pull the bulge
Push/Pull	P	Extrude a face; type a distance; the height snaps to other geometry. With a face selected first, click anywhere to pull it
Offset	F	Offset a face's outline in or out (the selected face, when there is one)
Move	M	Move or (Ctrl) copy; type a distance. With a selection, that is what moves, wherever you grab
Rotate	Q	Protractor: centre (on a face = its plane), reference, angle; type degrees
Scale	S	Green handles on the selection's box: corners uniform, side handles one axis, edge handles two; Ctrl scales about the centre; type a factor or sx;sy;sz
Follow Me	—	Select the path (edges, or a face whose outline is the path), then click the profile face to sweep it
Flip / Mirror	—	Mirrors the selection across a plane through its centre (→ ← ↑ pick the axis) or across a clicked face; Ctrl keeps a copy
Place Component	—

Hold a modifier for a tool: holding Ctrl orbits and holding Option/Alt pans until you release the key, then you are back in the tool you had. Which key does what is set in the Shortcuts tray (Shift can be assigned too; by default it keeps its selection meaning).

Inference as in SketchUp: green endpoint, cyan midpoint, red on-edge, blue on-face dots, black intersection crosses, axis-coloured lines, magenta parallel/perpendicular to an edge you rested the cursor on, dotted from point lines from points you rested on or clicked, guide points and lines, the centres of circles, arcs and polygons, and the origin. The arrow keys lock an axis (→ red x, ← green z, ↑ blue y) and Shift holds the inference under the cursor (a direction, a face's plane, or the axis a snapped point lies on): while it is down the point stays on that line and other geometry only projects onto it. Held, the point follows the cursor along the line and stops only where it meets an edge or inference line, or level with a corner right under the cursor. In Push/Pull, Shift keeps strictly to the face normal; without it the height is taken only from a corner, midpoint or centre right under the cursor. Points hidden behind faces never snap, also while moving. Lengths along inferred lines snap to 1 cm. Numbers typed while a tool is active go into the Measurements box.

Trays: Entity Info, Tags (layers), Materials, Outliner, Scenes, Section Planes, Display, Model Info, History, Plugins.

Hide and show: Edit ▸ Hide (⌘E) hides the selection, a group or component with everything in it; Unhide selected, last or all (⇧⌘E) bring it back, and the Outliner has an eye per row. View ▸ Hidden geometry shows hidden entities as ghosts you can select. Hidden entities stay in the document but leave slices and exports.

Face styles as in SketchUp, in the view bar and View ▸ Face style (⌥1–5): X-ray, Wireframe, Hidden Line, Shaded, Monochrome, plus Back edges (dashed lines for what is behind faces).

Light or dark: View ▸ Theme (or the Display tray) switches between System, Light and Dark for the chrome and the viewport; the choice is remembered in the browser, and the front page shares it.

Embedding

Another app can show a project in an iframe (/app?project=<id>&embed=1&owner=<key>): viewer mode with the looking, measuring and section tools only, driven over postMessage (storeys, views, zoom to an entity, selection, screenshots, any op). An app that keeps its own house model pushes it with the construction plugin's import_house (install the Construction plugin), which replaces the previous import and leaves what was drawn beside it. See docs/EMBED.md and web/public/embed-example.html.

MCP

Every tool is an MCP tool with the same semantics (draw_line, draw_rectangle, draw_circle, draw_polygon, push_pull, offset, move, rotate, scale, copy, erase, paint, make_group, explode, draw_arc, follow_me, mirror, make_component, place_component, edit_component, make_unique, add_guide, add_dimension, add_text, add_section, measure, …), plus project tools (list_projects, create_project, use_project, get_document, list_entities, undo, redo), viewport tools that drive the open browser (screenshot, set_view, set_camera, zoom_extents, zoom_to, zoom_window, previous_view, next_view, orbit, pan, zoom, select, activate_tool, get_view_state) and export_glb. screenshot returns a PNG of the viewport, so the model can look at what it built.

Plugins

The core knows only faces, edges, groups, guides, dimensions, texts and section planes. Everything domain-specific comes as a plugin with an engine half (Rust: custom entity types expanded into core geometry, custom ops that become MCP tools plugin.<id>.<op>, export formats) and a browser half (tools, panels, Entity Info). Plugins are installable packages: download a .plannr-plugin file and install it with Plugins → Manage plugins… → Install from file; the same dialog switches each one on and off and removes it. Their engines run as WebAssembly in a sandbox inside the server. A fresh Plannr has none: it is a plain SketchUp-style modeller until you add some.

They live in plannr-plugins, each with its own release:

Plugin
Construction	houses from rooms: storeys, rooms of any shape with shared walls built once, Belgian masonry (cavity walls coursed brick by brick, beam-and-block floors, lintels, foundations), doors and windows as real holes, flat / gable / hip / shed roofs, fixtures, pipe and cable runs, parametric furniture, takeoff, checks and U-values, the import of Uzzetje house models
Electrical	the installation to AREI/RGIE: board, circuits, conduits, checks, situation plan and one-line diagram (needs Construction)
Framing	Medeek-style wood framing: walls, floors, every timber roof type, beams, stairs, foundations, hardware, engineering check, plans, cut list
Plumbing	pipes with bends or fittings, valves, mixers, manifolds, brackets, checks, material list
Walking mode	first-person walk-through with every tool at hand, on desktop and phone
3D Print	3MF / STL for slicers, watertight check and repair, plate layout
Car Track	printable 1:64 die-cast track with connectors, supports and a test drive

See docs/PLUGINS.md to write one.

Document

One JSON document per project: layers, materials, entities (face, edge, group, guide, dimension, text, section, custom), scenes and per-plugin extensions. See docs/CONTRACT.md.

License

MIT — see LICENSE.