The title question isn’t one I get asked too often, but, when it comes up, it is something I love to show users, since there is a powerful tool that can help them. The Compare tool:
SOLIDWORKS provides the ability to compare two files or two configurations of a model using four different tests: Documents, Features, Geometry and Bill of Materials.
Compare Documents
This comparison checks the properties of the files to see how they differ. The few places that this option checks are File>Properties and Tools>Options>Document Properties. This can easily determine what document property settings may be different between the two files. It allows you to easily check the differences of templates and their default settings.
Below you can see the differences between the two files by the file properties as well as the part properties.
Compare Features
This comparison points out the differences between different versions of the same part using features. In other words, it analyzes the features to look for dimensional differences. Not to be confused with sketch dimensional differences. This function places model features into three categories: identical, modified and unique. Identical is obviously the same between the two parts/configurations, modified is the same feature but with differing parameter values and unique is specific to that version. One detail to note is SOLIDWORKS has a requirement that features must have the same name for them to be compared. If the feature names are different, then they will both show as unique.
As you can see in the screenshot below, there is one unique feature present in the bottom part and other features which were modified. You can see when I select on the “Handle” feature it displays the differences between the two.
Compare Geometry
This comparison checks the geometry of parts and assemblies to another similar file or configuration. The part comparison will check faces and volume similarities, whereas assemblies only check for volume similarities. Any modified or unique faces change color, whereas identical faces remain the original color. The Geometry Compare tool can also compare like surfaces only for face similarities, since surfaces don’t have any volume.
In the screenshot below you can see the two comparison types within geometry which are volume and face. There are colors for each that helps identify the faces/volume that is specific to each.
Compare BOMs
This comparison can check the BOMs of drawings and/or assemblies to determine if there are missing or extra columns and/or rows. The tool will find all BOMs listed within the file and ask you to pick the one you would like to use. One thing to note is if you would like to display the missing or extra rows, then you need to include the Part Number column in each BOM.
In the screenshot below, you can see the new BOM is missing a column. When selected, the Compare BOM tool will state which column is missing, as well as any additional columns and other fields.
I hope this clears up any questions regarding this tool and allows you to utilize the functionality to its full potential. Make sure to let us know in the comments section below which one you like the best.