I use solidwork for modeling part that will be machined in CNC machine. Before processed in CNC machine, the CAD model processed in Mastercam to get the G-Code. I usually use iges format for transfer data from solidwork to Mastercam.
I found a problem with the CAD model in Mastercam. here is the example:
The picture above is the example of automotive part CAD model that I made. I used extrude (solid feature) from the outline. Next, I used variable size of fillet, boundary surface, and cut surface, for making different size of chamfer (showed by the red arrow).
when I convert the model into iges and then opened in Mastercam, the wireframe has different type. see the picture below
no 1 outline is read by the mastercam as continuous line, the arc showed as arc and has radius value. it impact the tool (cutter in CNC milling) can move smoothly and resulting smooth surface.
but no 2 and 3 is read by the mastercam as dot to dot radius, not as a continuous arc. it impact the tool move roughly, and resulting rough surface.
it maybe because line 2 and 3 aren't shaped from shaped outline like no 1. but, how to make line 2&3 as good outline< so that it isn't needed to redraw 2&3 line in mastercam...
l have never used mastercam but as far as I know they have an add in so you can run it inside of SolidWorks.
If you cannot do this try exporting your part as a parasolid or step file for to bring across to Mastercam I know that in the list of file types to export from SW that parasolid or step is better than iges
If you can upload your files so we can have a look at them for you.