<p>I have a 3D printer that I built using CD-ROM drives. It's all set and ready to go but when I generate <code>.stl</code> or <code>.obj</code> files my G-code sender program cannot load it. I have found that Slic3r will export the <code>.stl</code> into G-code but it has the option of changing the <em>G-code flavour</em>, or <em>firmware</em>. </p>

<p>My machine is running from an Arduino Uno with Grbl v0.8. </p>

<p>So the question is, which firmware setting would be appropriate for my machine that would require the least amount of editing before I can print?</p>

From what I understand, you're trying to partition your object into smaller pieces with the hopes of putting them back together in a manner similar to a Jigsaw puzzle.
There are two options that I know of to do this, which requires using OpenSCAD:
The
PuzzleCut
library - This allows you to disassemble your object into a multiple pieces that can be assembled together in a jigsaw puzzle type manner
The
PinCut
library - This allows you to disassemble your objects into multiple pieces that than be reassembled using the pins and corresponding holes on the pieces.