I am using Makerware 2.4.1.24 to generate x3g files for printing. I select 'The Replicator (Dual)' and it shows both the Left and the Right Extruders. However, it only allows the use of the Right Extruder. There seems to be no way to select the Left. Am I using the correct software and version number? Also is 'Replicator (Dual)' the correct selection? The 'Replicator 2' selection only shows one extruder. 'The Replicator 2X' selection shows both extruders but the printer doesn't recognize the x3g files that it generates. The last selection, 'The Replicator' is also for a single extruder. Additional questions:

- What is infill?
- I have had difficulty printing without a raft, what is the reason for that when no raft is recommended above?
- The CTC manual isn't very clear. I did not install the ReplicatorG software. It was my inference that one uses either Makerware or ReplicatorG to convert the STL files to x3g. Is that correct, and if so, is one preferable to the other?