SeeMeCNC Rostock MAX v2 Assembly Manual page 309

The Extrusion option will thicken the lines used to draw the layers in order to give a more
accurate visual representation of what the actual print layer will look like when printed.
Finally, Sync to Print will allow you to follow the print process using the Layer View. As the
Orion prints your part, you'll see a real-time reflection of those moves. It's a pretty nice feature.
Rostock MAX v2 Assembly Guide
309