Skip to content
BOMproof

Free tool

Open a STEP file online and view it.

Drag your .stp or .step file here and rotate the 3D model right away. With product structure, BOM and a check on the model. Free, no account, and the file stays on your own computer.

  • Your file stays on your computer
  • Free, no account needed
  • Up to 150 MB, AP214 and AP242

Want to check your drawing and BOM too? Compare with the full BOMproof

01 How it works

Three steps, no installation.

  1. Step 1

    Choose your STEP file

    Drag a .stp or .step file into the box, or pick it on your computer. Up to 150 MB.

  2. Step 2

    Your browser reads the model

    Product structure, parts, materials and dimensions are read in your own browser. Nothing is uploaded.

  3. Step 3

    View, check, download

    Rotate the 3D model, see where duplicate or loose parts are and download the BOM as Excel or CSV.

02 Free or full

The viewer looks at the model. BOMproof looks at everything.

This free tool reads your STEP file. In BOMproof your drawings and BOM are added, and every check becomes a report that you work through.

What you can do Free tool BOMproof
View, rotate and search the 3D model
Product structure and BOM to Excel
Check for duplicate and loose parts and materials
Compare the BOM from Excel and from the drawing with the model –
Check title block, revisions and materials on the drawing –
Notes as balloons on the drawing, also as PDF –
Tick off notes and keep report versions –
Projects with multiple assemblies –
File size up to 150 MB up to 500 MB
Where your file is stored only on your computer storage in the EU
Price free free pilot

03 Explanation

What you need to know.

What is a STEP file?

A STEP file (extension .stp or .step) is the neutral format for exchanging 3D models between CAD packages. Its official name is ISO 10303-21. The file contains the exact shape of every part, the product structure (which parts are in which assembly and how many times) and often colours and materials too. The design history and sketches are not in it: you get the end result, not how it was modelled.

The common variants are AP214 and AP242. AP242 is the newest and can also contain dimensions and tolerances (PMI). SolidWorks, Inventor, Solid Edge, Creo, NX, CATIA and Fusion all export to STEP.

Opening a STEP file without a CAD package

Production planning, purchasing, a supplier or a customer does not always have a CAD licence, but does want to take a look at the model. With this viewer you open the file in your browser: nothing to install, no account. Rotate the model with the left mouse button, pan with the right one and zoom with the scroll wheel. With Wireframe you also see what is behind it.

More than just the 3D model

  • Structure: the design as a collapsible tree, with the quantity per parent assembly and search by name.
  • BOM: every part with the total quantity, the material and the dimensions, downloadable as Excel or CSV (see STEP to Excel).
  • Check: parts lying on top of each other, parts that are not attached to anything and missing materials, with a pin in the model (see STEP check).

Your file stays on your computer

The STEP file is read in your own browser and converted to a 3D view. Nothing is uploaded, so you can safely open confidential models here too. The 3D model is only stored in your browser, so the same file opens straight away next time. The reading of the product structure is the same one BOMproof uses when checking designs.

04 Frequently asked questions

Good to know.

01 How do I open a STEP file without a CAD package?

Drag the .stp or .step file into the viewer on this page, or click "Choose a STEP file". The model is built in your browser; you do not need to install anything or create an account.

02 Is my STEP file uploaded?

No. The file is read and processed in your own browser; nothing is sent to a server. Only the 3D model is stored locally in your browser, so the same file opens faster next time. If you consent to statistics, we anonymously count how often the tool is used and how large the models are; never file names or contents.

03 Which STEP files work?

STEP files with the extension .stp or .step (also .p21), in AP214 or AP242: the standard export of SolidWorks, Inventor, Solid Edge, Creo, NX, CATIA and Fusion. Unzip a zipped file first.

04 How large can the file be?

Up to 150 MB. Opening an 84 MB design for the first time took about half a minute on a laptop with 8 cores; after that the same file opens instantly from your browser. The larger the model, the more memory your computer needs.

05 What can I do with the viewer?

Rotate, zoom and view the model as a wireframe, search the product structure, view the BOM with quantities, materials and dimensions and export it to Excel, and see where duplicate or loose parts are.

06 Can I also measure or make sections with it?

Not yet. The viewer is meant for quickly viewing and checking a model. Dimensions per part (length, width, height) are in the BOM though.

Check model, drawing and BOM in one go.

The free tool looks at the 3D model. BOMproof puts your STEP model, PDF drawings and Excel BOM side by side and points out every deviation, in 3D and on the drawing. Book a demo with your own design.