TrueForm

For decades, enterprise CAD software companies have intentially obfuscated their files to create "vendor lock-in". Engineers hate their CAD systems, but can only dream of migration to better systems, that they will once again be locked into. While software has broadly seen explosive advancement, CAD has stagnated. Legacy file formats (STEP, IGES, OBJ, etc) are insufficient for reconstructing feature trees, and the CAD native file format remains locked behind closed doors. Hence we are stuck exchanging pdf drawings, and other lossy compressions of the rich machine readable detail embedded in the CAD native format.

TrueForm aims to change that, by creating an open DSL (domain specific language) with rich abstractions that mirror the tools you are used to in enterprise CAD, and then some. Critically, it provides an intermediate representation and compiler with interchangeable backend seams.

TrueForm is a declarative, intent-first modeling layer on top of OpenCascade.js, with a live-tested native OCCT transport/server path for the currently supported feature surface. It lets agents and web apps describe what a part is (features, constraints, assertions) without scripting kernel steps.

The goal: hardware design that feels more like software. A single, digital definition is authored that retains the information needed to produce all the digital assets required in the product development lifecycle.

GitHub: https://github.com/CPME/trueform

What It Is

• A deterministic intent IR compiled into B-Rep geometry.
• A stable selector system (datums + semantic queries) instead of face indices.
• A backend boundary that keeps kernel types out of authoring code.

What It Is Not

• A GUI CAD app.
• A free-form B-Rep editor.
• A promise of zero rebuild cost today.

Status

Current scope (v1) compiles a JSON-serializable IR and builds with an OpenCascade.js backend. Runtime target is Node + OpenCascade.js, with a parity-backed native OCCT path for the currently supported native feature surface.

Implemented part feature surface includes:

• Datums and sketching (datum.*, feature.sketch2d, sketch entities/profiles).
• Core solid/surface operations (extrude, surface, revolve, loft, sweep, pipe, mirror, shell, draft, thicken, unwrap, thread, hole, fillet, chamfer, boolean).
• Direct-edit and split operations (delete.face, replace.face, move.face, move.body, split.body, split.face).
• Staged surface and curve workflows, including trim/extend/knit and curve intersection.
• Pattern intent (pattern.linear, pattern.circular).

Consolidation note:

• Prefer sweep + explicit profiles for path sweeps and booleanOp(..., op, ...) for boolean operations.
• pipeSweep, hexTubeSweep, union, cut, and intersect remain available as compatibility aliases.

Staging note:

• Surface-mode variants for extrude, loft, sweep, pipeSweep, and hexTubeSweep, plus feature.trim.surface, feature.extend.surface, feature.knit, and feature.curve.intersect, are currently marked as staging in the runtime feature registry (/v1/capabilities.featureStages).
• The remaining advertised featureKinds are currently stable (see /v1/capabilities.featureStages).

Outputs are named and not limited to body:main; helpers default to body:<id> or surface:<id> depending on feature/mode.

Assemblies, constraints, and assertions are represented in IR. Core deterministic compile remains part-centric in v1, and assembly solving/runtime helpers are exposed under trueform/experimental.

Public package surfaces are also available as workspace packages:

• @trueform/core
• @trueform/dsl
• @trueform/export
• @trueform/api
• @trueform/service-client
• @trueform/backend-ocjs
• @trueform/backend-native

The root trueform package remains the compatibility facade.

Start Here

• Getting Started
• Architecture
• File Format (.tfp)
• DSL Quickstart
• DSL Reference
• API Reference

If you need deeper internal spec details, see the repo’s specs/ folder.