IFCCAD

Web page · Open the Explorer

IFCCAD is an experimental, open CAD drawing profile built on IFCX. It describes geometry, layers, blocks, layouts and drawing styles as typed, application-independent information. The Rust implementation validates drawings, reads and writes standalone files, and exchanges supported content with DXF/DWG while reporting conversion losses and numerical accuracy.

The profile and its encodings are still experimental, not a published standard. See the vision for the long-term direction and the roadmap for development priorities.

Try it in your browser

The IFCCAD Explorer lets you inspect drawing structure and properties, view the drawing, and compare conversion results. Open an IFCCAD, DXF or DWG file, or start with a built-in example. Drawing files are processed locally in your browser.

Example	What it shows
Entity catalogue	A numbered overview of all 16 current native entity families, Hatch fills, dimensions, blocks and drawing styles.
House floor plan	A fictitious house with rooms, openings, reusable blocks, dimensions and an A3 sheet at 1:100.

The catalogue is generated from an extensible sample registry. See example recipes to reproduce the drawings or add a sample, and the Explorer guide for inspection and conversion details.

Architecture and capabilities

The root Rust package is ifccad; its public API is ifccad::{IfccadDocument, load_ifccad_bytes, encode_ifccad_document, ...}. The model stays under src/ifccad. The core owns construction, shared validation, encoding and file IO and has no CAD runtime dependency. JSON/IFCX and experimental base-CBOR use the same logical model. CBOR mapping revision 1 and optional native Zstd transport revision 1 remain experimental; this migration changes neither their bytes nor semantics. The ifccad-cbor-zstd core feature is optional. The browser enables it for explicit experimental CBOR + Zstd downloads; ordinary IFCX download remains the default choice.

Neutral geometry, color, text, dimension, line-pattern, plot and workspace kernels remain in the core. The six cad-* companions own CAD preparation, numerical proof, presentation, text, dimensions, workspace conversion and preservation. ifccad-convert connects validated IFCCAD and opencadcodec CadDocument directly. Conversion, logical construction, encoding and storage remain separate responsibilities.

Current support includes primitive and planar/spatial path geometry, local blocks, Model/Paper layouts, appearance, simple and complex line patterns, Text/MText, viewports, workspace state, native SOLID/TRACE, Solid/LinePattern/Gradient Hatch and ordinary linear/aligned Dimensions. Font contours, complete dimension display and evaluated Hatch fill remain unassessed. The bounded opaque spline preservation route retains source capture separately from qualified CAD restoration.

The converter contract describes supported semantics, loss policy, source/target restrictions and the explicit codec repair. The Explorer uses this same conversion route. For IFCX / JSON input, the matching native download retains original source bytes. Experimental CBOR and CBOR + Zstd downloads encode the validated IFCCAD drawing projection.

Development sequence

ROADMAP.md is authoritative. The current order is:

1. Complete and integrate the IFCCAD-main-track migration after the accepted CBOR gate.
2. Resume Hatch B on the integrated basis, updating its scope to IFCCAD and reviewing any CBOR revision implications before contract changes.
3. The native SOLID/TRACE precursor is implemented, retaining all finite local corner combinations and both CAD object types, with coordinate, surface and display guarantees kept separate.
4. Add bounded worked-out Dimension graphics using the currently supported zero-width polyline profile; native storage, CAD exchange and Explorer support are implemented and verified.
5. Add polyline widths as a separate follow-up, using the red sample_AC1032 Dimension and its wide _ArchTick marker as an acceptance case.
6. Continue remaining Dimension kinds/selectors and later joint annotation support according to their dependencies.
7. Expand semantic coverage and assess physical storage using representative evidence.

Hatch B stays paused until migration integration. The xformop experiment stays separate. One broad cross-cutting task runs at a time; independent narrow work can proceed with focused checks and coordinated integration verification.

Repository layout

Path	Responsibility
src/ifccad, src/*_kernel, src/text, src/dimension	Active model and neutral kernels
crates/ifccad-convert, crates/cad-*	CAD adapters and numerical evidence
crates/viewer, crates/browser, format-explorer	IFCCAD CLI, WASM and Explorer
schemas/ifccad, conformance/next/ifccad	Active provisional contract
tests/fixtures/ifccad, examples/ifccad	Active readback fixtures and curated examples
legacy/ocdraw	Frozen reference source, tests and reproduction metadata
conformance/1.0.0, docs/benchmarks, benchmarks	Immutable releases / retained historical evidence

Using the implementation

From a checkout with the documented codec configuration, inspect or export the same example drawings with the CLI:

cargo run -p viewer -- ifccad examples/ifccad/entities.ifcx
cargo run -p viewer -- ifccad examples/ifccad/house.ifcx
cargo run -p viewer -- export-ifccad examples/ifccad/house.ifcx dxf

CAD input defaults to IFCCAD. --drawing-format ifccad remains accepted; --drawing-format ocdraw reports OCDRAW_PARKED before reading the input. See model IO conventions, the IFCCAD lifecycle, experimental contract and CBOR experiment.

Verification

python scripts/check_active_workspace.py
cargo fmt --all -- --check
cargo clippy --workspace --all-targets -- -D warnings
cargo test --workspace

On a fresh checkout, select the documented codec configuration and run cargo fetch once before the offline boundary audit. These commands cover only the active workspace, including its companions, converter, viewer and browser. There is no active compatibility feature that re-enables OCDraw. The boundary guard rejects parked packages, dependency paths and active Rust references to parked fixtures. Use focused checks during development, then one full gate for the final candidate prepared against intended main. Reuse requires comparison of all verification inputs, including ignored dependency patches/configuration, Cargo.lock, toolchain and environment. Keep per-worktree caches and build settings stable; coordinate expensive runs. See verification rules.

When changing native Zstd, also run cargo test -p ifccad --features ifccad-cbor-zstd --test ifccad_cbor_zstd and the corresponding feature-enabled Clippy check. Explorer changes require npm --prefix format-explorer test, the default WASM build and node format-explorer/tests/wasm-smoke.mjs as applicable. Measurements run only on explicit request and never as completion gates. Historical reports retain their original scope and checkpoint; they do not automatically describe later revisions. Numbered conformance collections remain immutable.

History and naming

IFCCAD was previously called IFCX-CAD. Project-owned APIs use IFCCAD; underlying IFCX syntax, .ifcx extensions and ifccad:: schema keys retain their meaning. The earlier package architecture using IFCDR/IFCPR remains retired. Today's IFCCAD has no OCDraw intermediate and does not revive that architecture. OCDraw is parked under legacy/ocdraw, outside ordinary builds and tests. Its complete frozen checkpoint remains recoverable; feature parity is not a development requirement. Legacy OCDraw files and explicit legacy Explorer selections return OCDRAW_PARKED. Licensed under MPL-2.0.

Local maintenance

Run pwsh -NoProfile -File scripts/cleanup_local.ps1 -Sizes to audit local worktrees, separate codec repositories and their build caches. Sizes are informational: there are no storage quotas or build limits. Cleanup follows task completion, with active work and measurement evidence preserved.

Removal requires an explicitly selected, completed and unused worktree. Cache cleanup defaults to main only; other checkouts must be selected individually. See local maintenance for the completion checklist, commands and protection rules.

For large CAD inputs, the report-only conversion diagnosis collects independent errors and blocked checks without pre-excluding entities.