AI for Parts & BOM Management
How to find the CAD file for a physical part with no part number: read the part, search by description and shape, and verify the match before reuse.
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7 min read
Michelle Ben-David
Michelle Ben-David is a mechanical engineer and Technion graduate. She served in an IDF elite technology and intelligence unit, where she developed multidisciplinary systems integrating mechanics, electronics, and advanced algorithms. Her engineering background spans robotics, medical devices, and automotive systems.
BOTTOM LINE
To find the CAD file for a part with no part number, start from the part itself: write down its function, material, key dimensions and distinguishing features. Use a photo to identify the type of part and its purpose, then search your vault by description and by shape rather than by number. Treat any candidate as a hypothesis and verify the controlling dimensions, the revision, the material and the assemblies it appears in before you reuse it. Leo offers search from image, description search across connected PDM systems and shape search, so each step feeds the next. Record what you learn in the part's metadata so the next search is easier.
A worn part lands on your desk. There is no tag, no drawing number and no engraved ID, just a bracket or bushing that somebody pulled off a machine and wants replaced. You are fairly sure your company modeled it at some point. The hard part is finding where, because the search box in your vault only answers questions you can phrase as a part number or a name that someone typed years ago.
This article walks through how to get from a physical part to the right CAD file in your own vault. It covers what you can read off the part itself, where a photo helps and where it does not, how description and shape searches fill the gap, and what a match still cannot confirm. It is written for engineers, technicians and product support teams who hold a part in their hand and need the model behind it.
Why a part with no part number is so hard to find
Vault search is built around labels. A part is found by its number, its name, its description field, a material or a project code. Every one of those labels was entered by a person, under deadline, following whatever naming habit was in force that year. When you hold a part with no label, you are asking the system to answer a question it was never indexed for.
The gap shows up in a few predictable ways. The part was designed by someone who has left, so nobody remembers what it was called. It was modeled before a naming convention existed, so its name is a project nickname. Or it came from a supplier drawing that was imported once and never renamed. In each case the file exists, and in each case a keyword search returns noise or nothing.
The cost is not only the time spent looking. When the search fails, the usual fallback is to measure the part and model it again. That creates a second file for the same part, with a new number, a new drawing and a new line in the bill of materials. Our article on why engineers redesign parts that already exist describes how large that duplicate effort becomes over a few years, and why PDM search fails engineers explains the keyword problem in more detail.
So the real task is not to search harder with the same terms. It is to turn the physical part into search inputs the vault can actually match: words, dimensions and shape.
IN PRACTICE
The geometry search has been invaluable, helping me find standard parts instead of designing new ones, saving a huge amount of time and effort. The search system is smart and CAD-aware.
- eytan s., R&D Engineer
Start with what you can read off the part
Before you take a photo or open a search tool, spend five minutes on the part itself. A surprising amount of identifying information is physically present even when no number is. Work through it in a fixed order so you do not skip the cheap clues.
Function. Say in one sentence what the part does: locates a shaft, spaces two plates, clamps a tube, guides a cable. Function words are the ones people tend to use in names and descriptions.
Material and finish. Note whether it is bronze, steel, aluminum or molded plastic, and whether it is plated, anodized or bare. Material is often a filter in the vault even when the name is useless.
Key dimensions. Measure the two or three that define the part: outer diameter, bore, length, flange thickness. Write down what the numbers are, not only the values.
Distinguishing features. A keyway, an oil groove, a knurled surface, a chamfer on one end. These are what separate your part from a dozen near-identical ones.
Markings. Casting numbers, supplier logos, date codes and partial stamps are easy to miss. A fragment of a number is still useful in a partial search.
Where it came from. Which machine, which assembly, which revision of the product. The location of a part in a product is a strong lead because it ties the part to a bill of materials.
Write the results down as a short record. You will use it three times: as the words for a description search, as the dimensions for a filter, and later as the checklist for confirming a match. A part with a measured bore, a named function and a known source machine is no longer anonymous, even if it still has no number.
Where a photo helps and where it does not
A photo is a fast way to hand a part to a search tool. It is also easy to overestimate. Knowing what the image can and cannot carry will save you from trusting a result that looks right.
What a photo is good at: recognizing the type of part and its purpose, narrowing a huge catalog to the right family, and suggesting what a buyable equivalent might be. If the question is "what kind of thing is this, and can I buy one," an image is an excellent starting point.
What a photo is poor at: scale, tolerance and hidden features. A picture of a bushing does not tell you whether the bore is 6 mm or 8 mm. It cannot show an internal groove, a hardness requirement or a plating specification. Two parts that look identical from the front can differ by exactly the dimension that decides whether they fit.
There is a second limit that matters for your own vault. Image tools that recognize parts are usually pointed at catalogs and supplier libraries, so their answer is a part you can purchase. The file you need is often a part your company designed, which has no catalog entry at all. For that, the photo is the start of the search, and the dimensions and shape you measured do the matching.
Our overview of identifying a part from an image or description covers the catalog-facing side in more depth. The sections below focus on getting from that first identification to a model in your own system.
Leo: searching by photo, description and shape
Leo is an AI assistant built for mechanical engineers, trained on more than one million pages of standards, books and articles. It connects to an organization's knowledge base, including PDM, PLM, local and network directories and ERP, and works as an intelligence layer on top of those systems rather than replacing any of them. Leo offers integrations with leading PDM and PLM platforms such as SolidWorks PDM, Autodesk Vault, PTC Windchill, Siemens Teamcenter and Arena PLM, among others.
For a part with no number, three of Leo's search routes work together. Search From Image takes a photo, recognizes the part, identifies its purpose and suggests replacements you can buy. That gives you the right name and family, which is often the missing piece. Description search lets you type what you wrote down in the earlier step, such as a flanged bronze bushing with an oil groove, and find parts in your connected PDM by what they are rather than what they were named. Shape search compares geometry instead of metadata, which suits the case where you can identify a similar model but not the exact one.
The value is the order of work. The photo tells you what you are holding, the description finds candidates in your vault, and shape search ranks near matches against each other. Each step uses information the previous one produced, and each returns results with a source you can open and check. For a closer look at the geometry step, see our article on finding parts by shape rather than metadata.
One boundary is worth stating plainly. A photo on its own does not prove a match against your own designs. It narrows the field and gives you words and a family. The confirmation still comes from comparing the candidate model with the part in your hand, which is the subject of the next section.
What a match still cannot confirm
Finding a likely CAD file is not the same as knowing it is the right one. A candidate model is a hypothesis, and a short verification pass turns it into a decision. Skipping that pass is how a plausible match becomes a wrong purchase or a wrong revision.
Check the controlling dimensions. Compare the bore, length and flange values you measured with the model. A difference of a fraction of a millimeter can mean a different variant.
Check the revision. The part in your hand may be an older revision than the current model. Look at the revision history and the change orders to see what changed and when.
Check the material and finish. The model may carry a material field that disagrees with what the part is actually made of, especially on older files.
Check the surrounding assembly. Open the candidate in the assembly it belongs to and confirm it mates with the parts around it in the way the physical one does.
Check for siblings. Look for a family of near-identical parts with different numbers. A different dash number can be the one that fits.
Check where it is used. A where-used list shows every assembly that contains the part, which confirms the context and shows who else depends on it.
The last check pairs naturally with where-used impact analysis, which lists the assemblies a part appears in. If the candidate shows up in the assembly the physical part came from, your confidence rises sharply.
Record the outcome. When you confirm a match, add the identifying description you wrote earlier to the part's metadata, so the next person who holds the same part finds it by words. When you find no match, you have a documented reason to create a new part, instead of a vague feeling that nothing exists.
FAQ
Find the part you already designed
Search your PDM by description, shape or photo.
Leo connects to your PDM, PLM and file directories so engineers can find existing parts by description or shape before anyone models a duplicate.
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