Prepare the latest available design files, the changes you need, the important dimensions and the intended use of the result. Include drawings, material information and supplier requirements when available. Tell your designer which CAD system and version produced the files, and agree the required delivery formats before work begins.
Start with the work you need done
Explain whether you need a new model, revisions to an existing part, an assembly or supplier documentation. Identify the features that must remain fixed and describe the next use of the files, such as design review, prototype preparation or manufacture.
This determines which inputs matter. A visual reference for a new product and controlled dimensions for an existing component serve different jobs.
Prepare a clear file set
| Input | What to include |
|---|---|
| Editable CAD, if available | Current parts, assemblies and referenced files, plus software/version information |
| Exchange files | An agreed format, such as STEP, for reviewing geometry in compatible software |
| Drawings | Applicable dimensions, tolerances, materials, finish and assembly requirements |
| Supporting material | Sketches, photographs, measurements, scan data, test findings or supplier comments |
| Revision information | The current approved version and a description of the requested changes |
NIST describes STEP as a product-data exchange format that can include geometry and product and manufacturing information. What actually arrives depends on the source file, export settings and receiving software. Check the received content, including any annotations, instead of assuming every STEP export contains the same information. NIST: STEP File Analyzer and Viewer
STL is a mesh representation of geometry. It can be useful for an agreed printing workflow, but the original editable model may be more useful for design revisions. Confirm units and the file format required by the intended supplier. Autodesk: STL export
Source: NIST: STEP File Analyzer and Viewer
Source: Autodesk: STL export
Explain requirements beyond the shape
Identify the surfaces that must fit together, important clearances, loads, operating conditions and material requirements. Mark unknown measurements and their source. A dimension estimated from a photograph should not be treated as a verified measurement.
Ask the intended supplier what information they need. For example, Protolabs' sheet-metal guidance requests a drawing to identify hardware types and locations when these are absent from the CAD. That is one supplier's process guidance, not a universal specification for every CAD project. Protolabs: Sheet metal quoting
If you need reverse engineering, describe the measurements, drawings or scan data you can supply. We Master Design's service does not imply in-house physical scanning or production.
Source: Protolabs: Sheet metal quoting
Confirm the handover before modelling begins
Agree the expected deliverables, software compatibility and revision naming. Clarify whether drawings, assembly information or a bill of materials are included. Keep the model and supporting documents aligned when a change is approved.
Supplier-ready documentation depends on the process and the actual requirements. Technical design and CAD and manufacturing-ready packages can address different parts of that work, with an agreed scope.
Prepare your CAD enquiry
Start a project with the current stage, the changes you need and the files available. If you are deciding what to request next, read prototype-ready versus manufacturing-ready files.
Further reading
Common questions
- Can I start without a native CAD file?
- Share what you have and explain the required result. A designer can assess whether an exchange file is sufficient or whether rebuilding geometry is part of the scope.
- Is a STEP file enough to manufacture a part?
- That depends on the part, the information contained in the file and the supplier. Confirm required materials, tolerances, finishes and other instructions before treating the package as complete.
- What should I do with large or confidential files?
- Use the project form for a brief and suitable small reference documents. Ask the team to agree an appropriate transfer method for larger or confidential CAD before sending it.
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