Open a STEP File in Your Browser. It Never Leaves Your Computer.
A viewer for STEP and IGES 3D models that runs entirely in your browser. Open a customer's model, turn it, hide parts of an assembly, read its overall size, and measure its volume, surface area and weight. The file is read on your own computer and is never sent to MechCircle or anyone else.
Included with every MechCircle account, in the Tools panel. Sign up free
How to use it
Open the STEP Viewer from the Tools panel and choose a .step, .stp, .igs or .iges file. The model appears with its parts listed; turn it, choose a standard view or switch to wireframe, and hide parts of an assembly to see inside. The overall size shows straight away. Press Measure for the volume and surface area, pick a material to get the weight, and save a PDF with a picture of the model and its figures.
Units are read from the file, and said
A model's sizes are only as good as the unit the file declares. The viewer reads the unit and its conversion factor from the file itself, converts everything to millimetres, and says what it found. These are the sentences it shows for four small files, produced by the viewer's own code:
What a STEP file declares, and what the viewer tells you
| The file declares | What the viewer says |
|---|---|
| Millimetres | The file declares millimetres. Everything below is converted to millimetres. |
| Metres (a common export setting) | The file declares metres (1 = 1000 mm). Everything below is converted to millimetres. |
| Inches, 1 inch = 25.4 mm | The file declares inches (1 = 25.4 mm). Everything below is converted to millimetres. |
| Inches, but 1 inch = 2.54 mm (a broken export) | The file says inches (1 = 2.54 mm) — but its inch is not the standard one. The importer follows the factor written in the file, so sizes may be wrong. Check one known size. |
The sentences are the viewer's own, produced by the same code that reads an opened file. A unit name whose factor is not the standard one is flagged rather than trusted.
What each column means
- The file declares
- The unit written in the file, and how many millimetres one of them is.
- What the viewer says
- The line shown above the model. A unit whose factor is not the standard one is flagged, so a broken export is caught before a size is quoted from it.
What happens to your file
Nothing leaves your computer. The file is read by your browser and turned into a 3D model by a program running in your browser. MechCircle never receives it, stores it or sees it, and the viewer saves nothing. That matters when a customer's contract keeps their models on your premises. The PDF you save is made on your computer too, and goes wherever you put it.
How the figures are worked out
- Overall size: the box the model fits in, along the file's X, Y and Z axes.
- Volume and surface area: measured on a finer version of the model made only when you press Measure. They read slightly low, by up to about 0.1%, and never high.
- Weight: the measured volume times the density of the material you pick from a list of standard materials.
How it helps
- Open a customer's model without installing CAD software
- Check the size and weight of a part before quoting for it
- Keep a customer's file on your own computer
- Save a PDF picture of the model with its figures to share
What it does and does not cover
- It is a viewer. It does not edit a model or make a drawing from it.
- No point-to-point measuring and no section views. The figures are the overall size, the volume, the surface area and the weight.
- The saved PDF is a picture of the model, marked as not a drawing and not to scale. Do not measure from it.
- STEP and IGES only: no native CAD files and no STL.
- An IGES file's declared unit is not read; sizes are as the importer converts them.
- Up to 10 MB on a computer and 2 MB on a phone, because the model is built in the browser's memory.
Good to know
What does the viewer run on?
It uses OpenCascade, an open-source CAD library, run inside your browser. Its licence and source are listed on our open-source page.
Ready to get started?
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