The AI design engineer that works to tolerance.
Give TolRnce a drawing, a supplier’s STEP file or a few sentences. It builds the parametric 3D model with its fits and tolerances, the manufacturing drawing and a cost estimate, and hands it to your CAD program ready to edit.
Rebuilds the feature tree in SOLIDWORKS, Fusion and FreeCAD. Opens anywhere as STEP.
Scroll to build a part. Click or tap the cube to test its fit.
From a drawing to a solid
Open a DWG or DXF, a photo of a drawing, or describe the part in words. TolRnce builds a real solid on the OpenCASCADE geometry kernel, with parameters you can change and features you can switch off.
- Reads
- DWG, DXF, photos of drawings, STEP AP203, AP214 and AP242
- Builds
- Extrudes, cuts, holes with ISO fits, revolves, fillets, chamfers, shells, patterns and bent tube
It reads a part the way you do
Drop in a supplier’s STEP file and a trained feature network labels every face: through holes, blind holes, counterbores, countersinks, slots, pockets, steps, bosses, chamfers and fillets. Each feature is checked against the exact geometry, and sizes always come from the geometry.
It also finds tube sockets, NPT ports and mounting holes, so a vendor part drops straight into an assembly.
- Holes
- Slot
- Corner rounds
Every hole knows its fit
Tolerances are part of the model: ISO 286 fits on holes and shafts, ISO 2768 general tolerances on the drawing, and a stack-up calculator for chains of dimensions. Try a fit on a ⌀20 bore.
Slides in by hand. Clearance 0.015 to 0.036 mm. In the H7/g6 sliding fit range.
Bore ⌀20 H7: 20.000 to 20.021 mm. The gap is drawn 100 times larger.
Assemblies that bolt together
Place parts with mates, then bolt a set of holes. Screw lengths come from the joint stack, every hole is checked for alignment, and clashes are caught before anything is made.
The bill of materials and the cost roll-up update as you go, with ISO screws, nuts, washers, dowels and bearings from the built-in library.
Panels, skids and tubing
Fittings, valves, gauges and manifolds come with ports. Connect them, and TolRnce routes tube around every part on the panel, places cushion clamps where tube crosses the strut, and writes the cut list.
The same works for vendor parts: their ports are found when you open the STEP file.
Into the CAD program you already use
Every part and assembly exports as a package of ordinary files. Open the STEP anywhere, or run a macro and get the full feature tree in your own CAD program, ready to edit.
| Item | File | What it’s for |
|---|---|---|
| 1 | part.step | The solid, for any CAD program. Assemblies keep their structure, with one product per part. |
| 2 | part.stl | A mesh for 3D printing and viewing. |
| 3 | drawing.svg | The manufacturing drawing: views, dimensions, hole table and ISO 2768 general tolerances. |
| 4 | solidworks_macro.bas | Rebuilds the feature tree in SOLIDWORKS. |
| 5 | fusion_script.py | Rebuilds it in Fusion. |
| 6 | freecad_macro.FCMacro cadquery_model.py | Rebuild it in FreeCAD or with CadQuery. |
| 7 | steps_*.md | Step-by-step instructions for SOLIDWORKS, Fusion, Inventor, Onshape, FreeCAD and AutoCAD. |
| 8 | bom.csv tube_cut_list.csv | The bill of materials, with standard and vendor parts, and the tube cut list. |
| 9 | cost_estimate.md | A rough cost per process and quantity, with design-for-manufacturing checks. |
Checked against public test data
We measure TolRnce on test files published by the US National Institute of Standards and Technology (NIST) and on independent tables of standard parts, and keep every score as a regression test.
| Characteristic | Checked against | Result | Status |
|---|---|---|---|
| Reading STEP files | 28 NIST test-case files, compared with OpenCASCADE’s own reader | 27 of 27 solids match to 0.01%. The mesh-only file is refused with a clear message. | Pass |
| Reading tolerances from STEP AP242 | NIST’s list of the annotations each test case carries | 404 of 415 read correctly (97.3%) | Pass |
| Standard part sizes | 137 values from bd_warehouse: ISO 273, 4762, 4017, 4032, 7089, bearings, pipe | 0 mismatches | Pass |
| Feature recognition | 606 test parts the network never trained on | 99.75% of faces labelled correctly | Pass |
| Feature recognition on real parts | 829 faces of holes dimensioned in NIST’s parts | 87% labelled as holes. Every feature is checked against the exact geometry before it’s shown. | Improving |
NIST test cases courtesy of the NIST MBE PMI Validation and Conformance Testing Project. NIST does not endorse TolRnce.
Your drawings stay with you
Design files are your company’s IP. TolRnce is built so they don’t have to leave your computer.
- Geometry runs on your machine
- The CAD kernel runs inside your browser or the desktop app. Drawings and STEP files you open are read there; there’s no TolRnce server they get uploaded to.
- The desktop app works offline
- It makes no network requests, so you can use it on computers without internet access.
- You decide what the AI sees
- The AI agent in the web studio sends your request and the current model to Claude, made by Anthropic, only when you ask it to do something.
- No lock-in
- Every part exports as STEP, and the macros rebuild it as native features in your own CAD program, where you own it.
Get early access
TolRnce is in early access for design and manufacturing teams. Tell us what you design, what CAD program you use, and what slows you down. We’ll set you up.
hello@tolrnce.com
- In your browser: the full studio, with the AI agent.
- Desktop app for Windows and macOS: works offline and saves .tolrnce projects. The agent comes to the desktop next.