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BOMproof

Free tool

Check your STEP model for duplicate and loose parts.

Parts lying on top of each other, parts that are not attached to anything and materials that are not filled in: you do not see them in the tree, but the shop floor does. This free check finds them in your STEP file and points them out in 3D.

  • 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 the free check finds

  • Duplicate parts: two or more instances of the same part in exactly the same place. If a whole subassembly is duplicated, you get one note for that subassembly, with the number of parts in it.
  • Different parts in the same place: often an old and a new variant that both stayed in.
  • Loose parts: parts that touch no other part, with the distance to the nearest part in mm. A gap of up to 3 mm is reported separately: usually a gasket, ring or shim that has not been modelled.
  • The same shape under other names: geometrically identical parts with different names, for example a copy that was not updated.
  • Materials: parts without material while the rest have one, and default values such as Default (Generic is ignored: it is too often the default on every part).
  • Export errors: geometry that is not attached to any part, placements without position and parts without a 3D shape.

Why this matters

You hardly see these errors in the tree of your CAD package, but they do end up on the BOM and on the shop floor: a duplicate part is ordered twice, a loose part is in the wrong place and a part with a default material such as Default gives the wrong weight. Every note gets a pin in the 3D model; click it and you see which parts it is about.

How the check works

The check reads the product structure and the position of every instance from the STEP file and compares the bounding boxes of all parts. Parts touch when their bounding boxes meet to within 0.5 mm. That is fast and also works for large designs, but it is not a collision check on the exact shape: a part lying inside the bounding box of another counts as touching. It is the same reading that BOMproof uses when checking designs.

What the check does not do

This free check only looks at the 3D model. BOMproof also compares the model with your PDF drawings and Excel BOM: quantities per position, title block and revisions, materials on the drawing against the model and contradictions between drawings. Every note is pointed out in 3D and on the drawing, and an engineer decides what happens with it.

04 Frequently asked questions

Good to know.

01 What does the free STEP check look at?

Parts or whole subassemblies lying exactly on top of each other (placed twice), different parts in exactly the same place, parts that touch no other part, the same shape under different names, parts without material or with a default material such as Default, and export errors such as geometry without a part.

02 Why are duplicate parts a problem?

A part that sits twice in the same place is invisible in the model, but it counts twice on the BOM. Then too much is ordered or made. With a duplicate subassembly, everything below it counts twice.

03 Is a floating part always wrong?

Not always. If there are a few millimetres in between, that is often a gasket, ring or shim that has not been modelled; the check reports that separately with the distance. A part that is far from everything is usually in the wrong place.

04 Does this also check my drawing and BOM?

No, the free check only looks at the 3D model. BOMproof also compares the model with your PDF drawings and Excel BOM: quantities, title block, revisions and materials, with every note pointed out on the drawing.

05 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.

06 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.

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.