Blobs and gaps? Cost and retract?

[Phgeis]

At the beginning ofeach line I have a small blob and at the end is a bit( 0.2 mm) missing!

Played around with cost and retraction but somehow the result does not change. What do these values exactly do? The short pop up help is not precise enough for my understanding. Could somebody clarify please?

Philipp

[Techbuilder]

I have this issue as well
would be nice to see if someone has a resolution

[jimc]

ok so its my understanding that coast stops pushing the filament out "x" amount of distance before a retraction or maybe a change in in direction, im not sure which. coasting allows the excess pressure in the tip to be relieved so even though the extruder isnt pushing the filament out the plastic doesnt continue to ooze. kinda like when you release the pressure from a caulking gun. the retraction pulls the filament back a bit during a "rapid" move to prevent ooze during the jump from one side of the part to another. i do believe the coast only happens on the rapids as well, not at the beginning and end of a line. for instance when zigzagging back and forth for infill, the starts and stops wouldnt apply to coast or retraction.