Free engineering software, built by engineers

Opens the formats that matter

STEP, IGES, STL, Parasolid (.x_t), 3MF, GLB, OBJ and more, including large assemblies, with an instant reopen cache.

Learn it by watching it work

Eight narrated tutorials, 83 steps, built into the app. These are not videos: an animated cursor drives the real interface, runs the real functions and speaks along, then leaves the finished work live for you to poke at. It starts on a full truck assembly and moves through CAX-IF, Autodesk FDM, Zenodo CNC and NIST AP242 benchmark parts. Pause, replay, skip, or run at 0.75× to 2× speed.

Real inspection tools

Measure vertices, edges and faces; section views; mass properties; interference checks; model scaling; exploded views with automatic, collision-screened disassembly sequences you can play back or export. A persistent Object Inspector, deterministic health and geometry-quality checks, and evidence-gated recognition of standard hardware. Click a finding to frame the affected parts.

The whole design review, start to finish

Mark up the model like a real review: named view bookmarks, issue pins tied to the exact camera view, redlines with captured measurements. Compare two revisions into a deterministic change map (modified, moved, added, removed) and find duplicate or similar parts by geometric fingerprint. Export it as CSV or a self-contained HTML/PDF review package, and save everything as one .p3dproject file: reopen it tomorrow, without the original CAD, exactly where you stopped.

Manufacturing checks before you cut or print

Repair meshes non-destructively (sanitation, normals, bounded hole filling, decimation) with deviation evidence and full undo. Audit a part for 3D printing against a printer profile you declare: build envelope, contact area, overhangs, thin walls, and a six-orientation comparison. Screen it for three-axis machining against your stated stock, travel and cutter: clearance, reach and access evidence across six setups. All of it runs locally and sits upstream of your slicer or CAM: it flags what needs attention and does not pretend to be either.

Drawings, PMI and tolerance stacks

Generate a conventional four-view drawing sheet (A4/A3/A2, ASME third-angle or ISO first-angle, hidden lines, envelope dimensions, title block) and export it as SVG, printable HTML or PDF. Read the GD&T the CAD author actually wrote into a STEP AP242 file: semantic dimensions, geometric tolerances, datums and graphical PMI, with integrity checks and a CSV audit trail. Then build a signed 1-D tolerance loop and solve it exactly: worst case, RSS and Monte Carlo, with contributors ranked by how much each one costs you.

AI Engineer built in, and you stay in command

Identify components, color by function, generate a BOM with cost estimates (formatted Excel export), review the design, or chat with your model through any OpenAI-compatible endpoint, or fully local and private with LM Studio. It can also drive the deterministic tools above: BOM, viewer commands, machining comparison, drawing generation, tolerance actions. Every proposed step is previewed with evidence and match counts, runs only after you approve it, and stays audited and restorable. The AI chooses which allow-listed action to run; the geometry and the engineering maths stay deterministic, and nothing invents design intent that was not in your model.

Estimates your cost savings: AI vs. manual labor

Every AI run is metered in real dollars, and the built-in cost & savings log estimates what the same work would cost an engineer doing it by hand, at your own labor rate. Each model session becomes a line item (AI cost, manual estimate, and money saved) with a running total.

Photoreal rendering

Ray-traced studio images and 4K exports: presentation-grade output straight from a browser tab.

Private by design

One HTML file that runs entirely on your machine. No install, no account, no upload, and your models never leave your computer. A ? button in the app lists every network touch this file can make, each with an off switch.