Combing-What is it really?

[kmanstudios 1,120]

I have seen this many times in topics. I do not get the explanation in the pop ups. And, I have never touched it until last night. I was trying to suss out an issue with a print and just punching buttons. I turned off combing and my print time estimate really increased. That is what is making me ask. I always figured that if you stop an action, you save time. Apparently not.

[neotko 1,417]

Combing instead of moving the from A to B search for paths of already printed areas to go though A to B. The intention is to avoid a retraction (in theory). There are more than one behavior on combing (no skin allows to remove scratches (or some) when using it with no retraction. 

 

Basically, times goes up because travels from A to B is longer, and also since UM marlins don’t have separated the Travel & Print accel/jerk when used it might (not aure of this 100%) as a Print move, so if the combing is done on the perimeters where accel/jerk is really low, then the speed of the move should be even slower. But I suppose Cura devs already change accel/jerk for combing so it’s done as a travel accel/jerk and not like a print one?

 

Anyhow, longer travel distances, more print time. 

[gr5 2,172]

retraction also takes time.  So sometimes combing speeds up a print because it doesn't have to retract.  Sometimes it slows down a print because it's not going direct from point A to B but sometimes going the long way around (so it can stay within the print).

 

I don't know why combing and retraction are inextricably linked - I wish this feature had 4 modes instead of just 2.  But lots of people turn off combing for the bottom layer to avoid ugly lines on the bottom layer.  Turning off combing means you get more retractions and fewer extra lines.

[kmanstudios 1,120]

30 minutes ago, gr5 said:

retraction also takes time.  So sometimes combing speeds up a print because it doesn't have to retract.  Sometimes it slows down a print because it's not going direct from point A to B but sometimes going the long way around (so it can stay within the print).

That would explain things....I had turned off retractions as I am wanting a 'grimy, vine' type of look.

[gr5 2,172]

Oh.  If retractions are off then definitely turning off combing will speed things up further.  and you will get more stringing for that "grimy vine" look, lol.

 

[gr5 2,172]

There is a "fuzzy skin" feature in cura you might try some time.  

[kmanstudios 1,120]

You will ahve to see the final to see what I was aiming for, but a bit of the drooloops philosophy at work here.