SheetCam can send the Gcode directly to Mach3. This eliminates you haveing to close and open files in Mach3 when you are making small tweaks to the job.
In order for SeetCam to send directly to Mach3, you need to have Mach3 and SheetCam running on the same machine.
You have to turn on the Mach3 communications feature by hitting the Mach3 sync button the toolbar shown here.
You will get a small dialog like this when SheetCam is talking to Mach3.
By default it is on the main screen, but you can drag it off the main window and on your desktop.
Now things will work identical to running the post processor in SheetCam, the only difference is that Mach3 will load the file you are saving as well.
As Mach3 moves the router, it will update SheetCam and the main cursor will follow the path that Mach3 is taking. The downside to this is that it only works if Mach3 is setup to do mm. It does not work correctly if Mach3 is set to inches. In this case you just ignore the cursor on SheetCam.