Dxf exported from solidworks leave with 2 points arrives with 100's

I have a closed vector that is a retrace of a mesh intersect that had 1000’s of points. I exported as a DXF to solidworks and it opens in solid works and it opens as 2 clean vectors. When it gets exported back from solidworks it has 100’s. Is there a setting in rhino that is causing this?

Not sure how you are using the term “vector” - what you are describing sounds like a polyline. I don’t know what Solidworks does with those either on import or export. What happens if you re-import the dxf directly in Rhino without going through Solidworks?

Make sure the DXF / DWG export options in SolidWorks are set to “Export All Splines As Splines”

DXF/DWG is a terrible choice for data transfer with SolidWorks.
Use IGES or STEP instead.

You don’t use ellipse and spline