What the modeller is

The modeller is a 3D editor written against this engine, in the same Dart, running on the same four backends. It imports a model, cleans it up, rigs it, poses it, lights it, renders it and exports it, and it does all of that to a document. The file on disk is what the document is saved to.

The rest of the design follows from that.

A document of commands #

The modeller never edits geometry in place. Every change is a ModelCommand: a named, serialisable object that takes a project and returns a new one, or refuses with a sentence somebody can act on. AddPrimitive, Extrude, SetMaterialField, BendJoint and SculptStroke are a few of about a hundred and thirty.

That gives three things a closure mutating a mesh can't:


A history that says what it holds	"Undo" versus "Undo move three objects". A menu item can only read the second off a command that carries a sentence.
A journal that survives a crash	The project file records the commands that made it, one JSON object per line. A file that fails to open still replays up to the step before the one that broke.
An agent that can drive the editor	The MCP tool table is the command list: one tool per command, with arguments taken straight off the command. A closure cannot be listed, described, or called by name.

The agent support was designed in from the start. An agent and a person reach the same document through the same doors, which is why a scripted scenario and a hand-driven session produce byte-identical files, and why the tutorial's cases are tested by replaying their journals from nothing.

Ten modes over one project #

Object mode, which is what a launch opens on: the outliner on the left, the properties panel on the right, the viewport between them

The mode switcher is one document seen ten ways, with no separate editor behind each mode. A mode is a rail of tools plus a panel that knows what those tools need.

Mesh mode, with the vertex/edge/face sub-mode rail and the mesh tools

Object places, moves and parents whole things. Mesh edits geometry at vertex, edge and face level, over a half-edge structure that can answer "which faces meet here" without searching. Material and Paint handle surfaces, one through fields and one through a brush. Sculpt makes the shape right and Retopo then makes it drawable. Animation has four sub-modes of its own: pose, weights, morphs and retarget.

Animation mode, weights sub-mode: the gradient shading that shows one joint's influence, and the brush that paints it

Scene is lights, shadows, environment and post. Render is the still image at the end of it.

Scene mode: lights and their gizmos, the environment preset, and what the frame looks like with them

What it does not try to be #

It is not Blender, and it isn't trying to become Blender. It has no node graph and no physics authoring, you can't unwrap a whole atlas by hand-drawn seams at once, and sculpting stops well short of ten million triangles. Each of those is a real program's worth of work, and shipping a bad one is worse than leaving it out.

What it does offer is the shortest path from "somebody sent me a scan" to "this is in my game and it animates". The tutorial walks that path six times, from six different starting points.

Render mode: the pass chain on the right, the tiles as they land, and the result

Where it runs #

It runs on macOS, Windows, Linux, iOS, Android and the web from one source tree. That is the same reach the engine has, for the same reason: nothing in the modeller goes past the HAL. The web build edits as well as displays, which is what the demo page covers.