drevier

I'm late to the party, but I went digging for this same information and worked backwards this way. Just go to #6 for the punchline. The output of the E value Calculating extrusion_per_mm mm3ToE (simple cylindrical volume/height ratio) extrusion_mm3_per_mm definition "Current mm^3 filament moved per mm line traversed" extrusion_mm3_per_mm initialized Rectangular cross section calculation for extrusion_mm3_per_mm You can see that Cura assumes a rectangular cross section and scales up extruded material through the flow variable for different types of beads that you can set in your profile. This would also confirm what they mention in their docs.