Typed Domain Grounding
A statically typed Kotlin DSL plus compiler and validation feedback gives LLMs a ground truth to work against — the same principle that makes kUML reliable, applied to engineering data.
Kotlin DSL · ISO 10303 · AP242 · CAD · Engineering
Engineering that compiles.
One typed source. STEP-native models. Readable for humans and AI.
kSTEP is the first AI-first, code-first, STEP-native engineering modeling DSL for Kotlin/JVM. It brings Typed Domain Grounding — the architecture proven in kUML — to physical engineering: a statically typed DSL plus compiler feedback that gives humans and LLMs a reliable ground truth, from product structure to geometry.
Bracket.kstep.kts
// Bracket.kstep.kts — no imports required, kstep script host provides them
product(name = "Bracket-42") {
description = "Mounting bracket, aluminum, 4-hole"
partNumber = "BRK-42"
partVersion(id = "C") {
approvalStatus = Approved // type-safe enum, not a string
approvedBy = "J. Betchvaia"
}
}
// kstep render Bracket.kstep.kts --out Bracket.step (STEP Part 21 / AP242)Target syntax — sketched for M1, not shipped yet.
Code-first. AI-first. STEP-native.
Today's CAD world offers GUI suites with proprietary formats — or code-first scripting without real AI integration. kSTEP is the deliberate third way.
STEP-native, not proprietary
kSTEP speaks ISO 10303 directly — AP242, Part 21 export, product structure and beyond. No binary vendor formats, no lossy conversion.
A proven geometry kernel
Geometry builds on OpenCascade (OCCT), accessed via JNI on the desktop first — with a WASM path already open for a later browser playground, from the same codebase. Several foundation pieces already work end to end: real B-Rep solids (boxes, extrusions, filleted edges) with a first parametric feature-history layer, a 2D constraint solver (PlaneGCS) resolving coincidence, distance, alignment, parallel, and perpendicular constraints, geometry merged with product structure in a single STEP file, glTF/GLB export, and an interactive desktop viewer (orbit, pan, zoom, per-part material colors, smooth shading on curved surfaces). Full sketch authoring, stable geometric edge identity, and undo/redo are still ahead.
AI-first, not AI bolted on
LLM agents are a first-class user of the DSL — named parameters everywhere, validation loops, and an MCP server that already exposes the DSL as tool-calling tools, mirroring what kUML already ships.
Type safety as a feature
CadQuery and Build123d are Python — no static types, no compiler feedback. Kotlin's type system is kSTEP's deliberate differentiator, not an accident of language preference.
Open source, license-clean
Apache 2.0 for kSTEP's own code, dynamically linked against LGPL OCCT and PlaneGCS. Cleared deliberately during Discovery — no GPL traps.
Follow the build.
The repository is real, the milestones are public, and every step lands in the open.
kSTEP on GitHub