Simplify3D Skirt/Brim plus pressure advance = Stutter

Ak Eric

Note, I don't use pressure advance, but when I switched to RRF (from other firmwares like Reptier, Marlin, and Sailfish), I definitely noted more stuttering during the skirts/brims. Never put much though to it (since while slightly annoying, seemed harmless), but figured I'd put it out there.

jpwheless

I'm seeing similar issues, but not just for the skirt/brim.

https://www.duet3d.com/forum/thread.php?id=3745

dc42

It is normal for skirts generated by S3D to stutter when printed. It's because S3D generates a sequence of normal printing moves interspersed with short non-printing moves. I've no idea why it does that. Fortunately, it doesn't do that in the print itself.

totalitarian

@dc42:

It is normal for skirts generated by S3D to stutter when printed. It's because S3D generates a sequence of normal printing moves interspersed with short non-printing moves. I've no idea why it does that. Fortunately, it doesn't do that in the print itself.

That's what I suspected. Might have a play with the post processing and see if I can move the pressure advance code to after the skirt

nikker

Using S3D as well and see the same. Wondered why, nice to know now

totalitarian

Came up with this post processing command

[[language]]
{REPLACE "perimeter\nG" "perimeter\nM572 D0 S0.1; Pressure advance\nG"}
{REPLACE "; solid layer\n" "; solid layer\nM572 D0 S0.1; Pressure advance\n"}
{REPLACE "fill\n" "fill\nM572 D0 S0; Pressure advance\n"}
{REPLACE "; skirt\n" "; skirt\nM572 D0 S0; Pressure advance\n"}
{REPLACE "; bridge\n" "; bridge\nM572 D0 S0.1; Pressure advance\n"}

Basically is disables pressure advance for the skirt and infill. Change the [c]S[/c] value to suit your needs

totalitarian

dc42 once M572 D0 S0 is set, do we have to redefine M376 again? or can we just do it just the once?

EG,

M572 D0 S0.1; Pressure advance
M376 H10; fade compensation
….
M572 D0 S0; Pressure advance
....
M572 D0 S0.1; Pressure advance
M376 H10; fade compensation (required again?????)

AndreS

@nikker:

Using S3D as well and see the same. Wondered why, nice to know now

G1 X114.400 Y60.353 E0.0145
G1 X114.412 Y60.348 E0.0006 <–
G1 X119.159 Y58.485 E0.2369
G1 X119.172 Y58.481 E0.0006 <–
G1 X119.466 Y58.375 E0.0145

because of the marked G-Code, that S3D generates for skirt.

dc42

That's right. The ratio of extrusion to movement is different in the lines indicated compared to the surrounding lines, which is what causes the problem.

bot

It seems to be that S3D generates the skirt by duplicating every vertex and connecting the duplicate vertexes to draw the outline… making a segment that is a function of the skirt offset distance. In theory, by choosing a larger offset you may be able to mitigate this... but that seems like a bad solution to a silly problem.