Hi @Josh10 ,
that Plugin looks quite old (18yrs old at Rhino v3 times)
Unfortunately 3DM files are poorly supported by solid modelers.
Solidworks does import Rhino geometry (not curves) but you loose all layers hierarchy. More info here
This can be ok if Rhino file does contain few objects but can be a nightmare if you have to deal with more elements.
The only solid Modeler I found which manages correctly Rhino files converting layers to parts is SpaceClaim.
Best way I’ve found from Rhino to SW is create a block for each element then export to STEP. This way you’ll find blocks translated as parts in SW.
Alternatively you can create separate STP files for each part / layer.
An easier workflow would be to be able to convert layers (and their hierarchy) to blocks on the fly before exporting to STP.
this could a STP export option or a plugin as discussed already with @pascal