Vendor Supplied Data - It Can Be A Minefield

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As a CAD designer, I rely on vendor-supplied data to save time and ensure accurate component representation in my drawings. This data is a great tool when it is correct and valid. However, a careful review of this data is necessary to safely use it in your design work.

Vendor data is usually available in two formats; Manuals with PDF data, extractable with AutoCAD, or raw DWG /DXF data. It will have been done to fit the page format when pulling PDF data. This means that scaling is potentially random, as the image must be sized to fit a printed page. With a DWG / DXF file, the same level of caution must be applied, as some vendors will scale their data to fit a specific drawing sheet size.

Failure to verify the accuracy of the data you are using will cause potential errors in the design. This leads to lost time and money spent to redo not only drawings but fabricated details as well. It may be easy to fix a drawing. Not so much if you are taking a made detail.

The example below is a vendor-supplied CAD model. Is it accurate? Is it at scale (if so, what scale)?

I used the "distance" command *not* "dimension" to verify the data. You can see the distance vertically is 3.5, not 1.38. To look at the drawing, this is not necessarily obvious.

After verifying that my linear dimension scale is correct at one and determining that the actual scale of the item is 2.5:1, I scaled the image down and did a linear dimension to verify it. Now my design will be based on accurate data, eliminating potential problems in the future.

By taking the essential step to verify the accuracy of external data, many issues are avoided, as are the costs related to them. By having known good drawing data and saving the file to your server, others will also be more efficient.

This verification process should also be applied to any external data files you get, regardless of the source. You do not know how or how accurately something was drawn - don't trust it. Verify it!