Datum

Parametric 3D CAD that opens in your browser.

Sketch, constrain and extrude real parts, put them together in assemblies and make the drawings for the workshop. Datum is free to use; Datum Pro is one payment, with no subscription.

Open Datum free See pricing

Web app in Chrome, Edge, Firefox or Safari · Mac · Windows · Linux through the web app

Datum with a part open: the feature tree on the left lists the extrude, fillet, shell, cut and pattern that made it, with the ribbon of modelling tools above.

Design

Everything you expect from desktop CAD

Datum works the way SolidWorks, Fusion and Onshape users already think: a sketch, a feature, a feature tree you can roll back and edit. The geometry comes from OpenCascade, the same kernel that powers FreeCAD.

Parts

Extrude, revolve, sweep and loft; fillet, chamfer, shell, draft and patterns. Equations, configurations and several bodies in one part.

Assemblies

Insert parts and place them with mates, including gear, slot and limit mates. Exploded views, patterns and interference checks.

Drawings

Standard views, sections and details, dimensions that follow the model, GD&T, thread callouts and your own title blocks. PDF, DXF and SVG.

Sheet metal

Base and edge flanges, hems and holes, then flatten the part and export the flat pattern as DXF for the laser.

3D printing

Print-ready threads, heat-set insert holes, overhang and wall-thickness checks, and 3MF or STL export standing the right way up.

Analysis

Mass properties, measure, section views and a Quick Checker that watches as you work. Strength Check and QuickSim CFD in Pro.

AI assistant

Ask for a part in plain words and watch it build feature by feature, or connect Claude or ChatGPT. Optional, and off until you turn it on.

Open files

STEP, STL, OBJ, 3MF, DXF, SVG and PDF. Your parts are plain files on your computer that any CAD package can read.

Drawings

Workshop drawings in one click

Make Drawing lays out the front, top, side and isometric views on an A3 or ANSI sheet with a filled-in title block. Change the model and the views and dimensions follow.

  • Section and detail views with hatching
  • GD&T: datum features and geometric tolerances
  • Your own templates, including DWG and SolidWorks sheet formats
  • Exploded assembly drawings
A Datum drawing on an A3 sheet: three standard views and an isometric view of the panel housing, with a title block.

Pro plug-ins

Simulation without leaving your model

QuickSim CFD puts the part in a wind or water tunnel. Pick the fluid, the speed and the direction, and see the pressure on the part, the flow lines and the drag in seconds, in the browser.

  • QuickSim CFD OUT NOW
    Air or water from any side; drag, lift and the drag coefficient
  • QuickSim FEA COMING
    Stress, deflection and safety factor under load
  • QuickRender COMING
    Photo-real pictures, turntables and exploded animations
  • QuickOptics COMING
    Lenses, mirrors and light paths, ray-traced through your parts

Plug-ins that are not out yet are 20% off if you pre-order. They unlock by themselves the day they ship.

QuickSim CFD in Datum: a block in a wind tunnel, coloured by pressure, with flow lines streaming past it.

Switching

Feels familiar from the first click

Coming from another CAD package? Datum meets you halfway, and teaches the rest as you go.

Your mouse, your way

Turn, pan and zoom with the same buttons as SolidWorks, Fusion or Onshape. SpaceMouse works too.

Names you know

Commands can use the names from your old package, or plain words such as "pull a sketch up".

Learn inside the app

Short hands-on tutorials tick themselves off as you go: your first part, sketch relations, sheet metal, assemblies and drawings.

Nothing to install

Open a link and start modelling. Your work saves itself, with automatic backups and crash recovery.

Compare

Free, Pro and the plug-ins

Each licence is for one platform and is yours to keep. Every Pro plug-in is its own licence, on top of Datum Pro.

FreeProPro + plug-in
Design
Parts, sketches, equations and configurations
Assemblies and mates
Sheet metal and flat patterns
3D-printing tools and checks
Import and export in every format
Documentation
Drawings with views, dimensions and title block
Drawings without the Datum Free mark
Your own templates and GD&T
Exploded views and assembly drawings
Analysis and simulation
Measure, mass properties, section views, Quick Checker
Strength Check and Airflow Check
QuickSim CFD, and the plug-ins to come
Use
Web app
Desktop apps and the Claude / ChatGPT connector
Commercial use
AI assistant (pay-as-you-go credits or your own key)

Datum is in testing: until Pro goes on sale, every tool that is out, including QuickSim CFD, is free for everyone.

Why Datum

Made to be owned, not rented

Pay once

No subscription and no yearly maintenance fee. Updates to the version you bought are included.

Your files stay yours

Models are saved on your computer, not in our cloud, in formats other CAD packages can open.

Education discount

Students and teachers get 20% off Datum Pro and the plug-ins with code EDU20.

From a small studio

Datum is made by Inverse Square in Gloucester, UK. Questions go to the people who build it.

Model your next part in Datum

It opens in a browser tab, and the sample part is ready to explore.

Open Datum freePricing