Hello Everyone. Sorry for the n00by question, here it is: I am confident in using slicing tools like slic3r. They give you the possibility to set velocities (i.e. velocity on the perimeters, on the infill ... [manual.slic3r.org] ) As a result, when I generate the G-Code, I have this kind of output: [...previous lines...] G1 Z147.200 F7800.000 G1 Z149.400 F7800.000 M107 M104 S0 ; turn off temperature G28 X0 ; home X axis M84 ; disable motors ; avoid_crossing_perimeters = 1 ; bed_size = 200,200 ; bed_temperature = 0 [cut] ; first_layer_speed = 10 ; first_layer_temperature = 205 [cut] ; bridge_speed = 40 ; external_perimeter_speed = 30 ; infill_speed = 40 [etc] The question is: How this firmware extract the "speed" information when needed ? I expected some firmware instructions (like M220: Set speed factor override percentage) in the G-CODE when passing i.e. from infill to perimeters... but this is not true ! so how the firmware "decides" when we are on a perimeter or in a infill and how does it set corresponding velocities ? Similar consideration can be done for accelerations. [this is because I am writing a custom firmware] Thanks a lot, Paolo https://reprap.org/forum/read.php?267,568049,568049#msg-568049 Thu, 12 Mar 2026 16:05:11 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?267,568049,568134#msg-568134 https://reprap.org/forum/read.php?267,568049,568134#msg-568134
That info is contained in F parameters of the G0/G1 instructions (also if the terminology "feedrate" can be disguising :S [reprap.org] )

This generates new questions in me, but this is matter for another section of these forums.

cya]]> emdcp Repetier Thu, 08 Oct 2015 09:53:47 -0400 https://reprap.org/forum/read.php?267,568049,568049#msg-568049 https://reprap.org/forum/read.php?267,568049,568049#msg-568049
Sorry for the n00by question, here it is:

I am confident in using slicing tools like slic3r. They give you the possibility to set velocities (i.e. velocity on the perimeters, on the infill ... [manual.slic3r.org] )

As a result, when I generate the G-Code, I have this kind of output:

[...previous lines...]
G1 Z147.200 F7800.000
G1 Z149.400 F7800.000
M107
M104 S0 ; turn off temperature
G28 X0 ; home X axis
M84 ; disable motors

; avoid_crossing_perimeters = 1
; bed_size = 200,200
; bed_temperature = 0
[cut]
; first_layer_speed = 10
; first_layer_temperature = 205
[cut]
; bridge_speed = 40
; external_perimeter_speed = 30
; infill_speed = 40
[etc]

The question is:

How this firmware extract the "speed" information when needed ?
I expected some firmware instructions (like M220: Set speed factor override percentage) in the G-CODE when passing i.e. from infill to perimeters... but this is not true !
so how the firmware "decides" when we are on a perimeter or in a infill and how does it set corresponding velocities ?

Similar consideration can be done for accelerations.

[this is because I am writing a custom firmware]

Thanks a lot,
Paolo]]> emdcp Repetier Thu, 08 Oct 2015 05:55:29 -0400