Cura Time Estimates - UltiGcode vs. RepRap?

[eldrick 65]

I notice that the print time estimates change substantially depending on what type of code is generated.

With one print the estimated print time was 6hrs. 9min. when set to UltiGcode in the machine settings (for my UM2) vs. 5hrs. 20min. when set to RepRap Marlin. This is with 14.04RC1.

Can anyone tell me if this represents real printing time? Does the RepRap flavor of gcode really print around 15% faster than UltiGcode?

 

[gr5 2,224]

In general both printers can print at the exact same speed if you use the exact same acceleration and jerk settings and for the most part the acceleration and jerk settings can be set identically on both machines. I think only the retraction speed can be significantly faster on the UM2.

Cura doesn't ask what the acceleration and jerk settings are so it must assume some values. These values only started getting used in the print time estimates recently. It made a huge improvement on time estimates.

I suspect the main difference is because it probably uses these for UM2 but not for UM time estimates. I wish there was some advanced setting where you could tell cura what the acceleration and jerk settings are. The older Cura assumed infinite acceleration and so the estimates would be much too short.

 

[Daid 306]

Difference might be related to retraction, UltiGCode might calculate the retraction times wrong. Can you try with both retraction enabled and disabled to see what difference that makes?

 

[eldrick 65]

Difference might be related to retraction, UltiGCode might calculate the retraction times wrong. Can you try with both retraction enabled and disabled to see what difference that makes?

 

RepRap w/ Retraction enabled = 4h 3m

RepRap w/ Retraction disabled = 4h 3m

 

UltiGcode w/ Retraction = 4h 31m

UltiGcode No Retraction = 4h 31m