Fileloom STEP Lite

Lightweight Kotlin/JVM STEP/STP preview parser for Fileloom CAD wireframes.

This parser is intentionally not an OpenCascade binding and does not bundle WASM, native code, generated meshes, or heavyweight dependencies. It references the @tx-code/occt-js / occt-import-js style of returning a normalized import result, but narrows the implementation to fast text parsing and preview geometry that is cheap enough for Fileloom's Android app bundle.

Current Scope

• Reads ISO-10303-21 STEP/STP text files from an InputStream
• Detects bounded input size before building in-memory model structures
• Extracts PRODUCT name, unit hints, CARTESIAN_POINT, VERTEX_POINT, complex point/vertex records, DIRECTION, VECTOR, AXIS2_PLACEMENT_2D, AXIS2_PLACEMENT_3D, complex direction/placement records, LINE, POLYLINE, POLY_LOOP, complex line/polyline/loop records, CIRCLE, ELLIPSE, PARABOLA, HYPERBOLA, complex conic records, B_SPLINE_CURVE, B_SPLINE_CURVE_WITH_KNOTS, BEZIER_CURVE, QUASI_UNIFORM_CURVE, UNIFORM_CURVE, complex rational B-spline records, TRIMMED_CURVE, SURFACE_CURVE, SEAM_CURVE, OFFSET_CURVE_3D, COMPOSITE_CURVE_SEGMENT, COMPOSITE_CURVE, complex curve wrapper records, EDGE_CURVE, ORIENTED_EDGE, EDGE_LOOP, and complex edge records
• Emits lightweight line, polyline, closed poly-loop, closed edge-loop, circle, arc, sampled ellipse, sampled parabola, sampled hyperbola, sampled B-spline, sampled Bezier, sampled rational B-spline, and bounded composite line/polyline/B-spline/trimmed-conic wireframes with 3D bounds for preview adapters
• Counts unsupported curve records instead of flattening them into misleading straight lines
• Emits unreferenced finite VECTOR-backed LINE, bounded POLYLINE, B-spline, composite, Cartesian- and parameter-trimmed TRIMMED_CURVE, SURFACE_CURVE, SEAM_CURVE, OFFSET_CURVE_3D, full CIRCLE, and full ELLIPSE curves for wireframe/geometric-set style STEP exports without EDGE_CURVE topology
• Honors EDGE_CURVE same-sense direction for circular arcs, polylines, sampled ellipses, and sampled B-splines
• Resolves TRIMMED_CURVE, SURFACE_CURVE, SEAM_CURVE, and OFFSET_CURVE_3D wrappers to their lightweight basis curves before preview conversion
• Applies AXIS2_PLACEMENT_2D and AXIS2_PLACEMENT_3D direction/ref-direction axes when sampling ellipses and non-XY circles
• Has no runtime dependencies beyond the Kotlin/JDK standard libraries
• Publishes as dev.jaeyoung:fileloom-step-lite

This is not a full B-Rep kernel. Faces, triangulation, colors, assemblies, and exact topology are future additive work.

Usage

val result = StepLiteParser().parse(inputStream)
when (result) {
    is StepLiteParseResult.Success -> {
        val document = result.document
        println(document.name)
        println(document.entities.size)
    }
    is StepLiteParseResult.Unsupported -> {
        println(result.reason)
    }
    is StepLiteParseResult.Failure -> {
        println(result.message)
    }
}

Build

./gradlew test
./gradlew check
./gradlew publishToMavenLocal

The module is configured with maven-publish, signing, group = "dev.jaeyoung", and artifact ID fileloom-step-lite. The check lifecycle runs checkPublishedArtifactFootprint, which keeps the parser jar under its size budget and rejects native or WASM payloads.

Maven Central

Create and verify the dev.jaeyoung namespace in Central Portal before running a remote publish. If you want to publish snapshots before the first release, open that namespace in Central Portal and select Enable SNAPSHOTs first. The build uses only Gradle's built-in publishing/signing plugins.

Create a Central Portal user token and set its username/password as Gradle properties or environment variables:

export MAVEN_CENTRAL_USERNAME="..."
export MAVEN_CENTRAL_PASSWORD="..."
export MAVEN_CENTRAL_NAMESPACE="dev.jaeyoung"
export SIGNING_KEY="$(cat private-key.asc)"
export SIGNING_PASSWORD="..."

Check publish inputs locally without uploading:

./scripts/require-maven-central-env.sh snapshot
./scripts/require-maven-central-env.sh release

The release preflight intentionally rejects MAVEN_CENTRAL_NAMESPACE values other than dev.jaeyoung so this artifact cannot be staged under the wrong Central Portal namespace. Manual release versions must be artifact versions such as 0.1.0; the accepted shape is MAJOR.MINOR.PATCH with an optional qualifier such as 0.1.0-rc.1. Tag pushes may use v0.1.0 because the workflow strips the tag prefix before publishing.

Publish a snapshot:

./gradlew publishAllPublicationsToCentralSnapshotsRepository

Or run the Publish Maven GitHub Actions workflow with target snapshot.

Publish a release candidate:

./gradlew -PreleaseVersion=0.1.0 publishAllPublicationsToCentralReleaseRepository

For GitHub Actions, set repository secrets named MAVEN_CENTRAL_USERNAME, MAVEN_CENTRAL_PASSWORD, SIGNING_KEY, and SIGNING_PASSWORD. Then either run the Publish Maven workflow with target release and a release_version such as 0.1.0, or push a tag such as v0.1.0.

Release artifacts published through the Central Portal OSSRH Staging API still need to be uploaded from the staging compatibility service into Central Portal. The GitHub workflow runs this step automatically after a release upload and asks Central Portal to attempt to automatically release it to Maven Central after validation:

curl --fail-with-body \
  --request POST \
  --header "Authorization: Bearer $(printf '%s:%s' "$MAVEN_CENTRAL_USERNAME" "$MAVEN_CENTRAL_PASSWORD" | base64 | tr -d '\n')" \
  "https://ossrh-staging-api.central.sonatype.com/manual/upload/defaultRepository/$MAVEN_CENTRAL_NAMESPACE?publishing_type=automatic"

Publishing references:

• Central Portal Gradle guidance: https://central.sonatype.org/publish/publish-portal-gradle/
• Central Portal OSSRH Staging API: https://central.sonatype.org/publish/publish-portal-ossrh-staging-api/
• Central Portal snapshots: https://central.sonatype.org/publish/publish-portal-snapshots/

License

Apache-2.0. See LICENSE.