The best way would be to get a laser scan for reference, or get points from a Faro arm probe (or similar).
If you don't have Scan to 3D in your SolidWorks license, the laser scan, or point cloud, can only be imported as a Graphics Body, useful for visual reference or tracing by eye (you can't snap to it or get sections from it.)
I've recently discovered CloudCompare (free, open source) can make sections through point clouds that you would get from a laser scanner and output vectors. (I have used Geomagic to get vector sections in the past but its expensive software). I still have not fully tested CloudCompare for this, but it seems like it might be an option. The sections through the point cloud import into SolidWorks as sketches, which could be used to create new curves to build surfaces. (The curves generated directly by the sectioning are rough, and so are not useful to generate surfaces themselves)
Photogrammetry could also work too.
There are several programs which will allow you to use many photos of an object from different angles to create reference points for building a model. Some of these apps don't have the tools to record specific points and will generate an overall mesh of the object. Photomodeler has been around for many years, and since it started as a specific point measuring tool, its likely it still has that functionality.