Lines in first layer

[mcdavidr 0]

Any ideas on how to get rid of threads that printhead drags when traveling to new spot. I have retraction enabled, z how when retracted enabled. They make the face of print look terrible. I3 Mega.

 

[mnis 11]

One way I know: Let Cura print concentric, then the basic shape is driven from the outside to the center and there are no intersecting lines.

 

Cura v3.3.1 ... Settings for housing:
Lower / upper pattern.
Lower pattern for first layer.

Edited May 21, 2018 by mnis

[cjs 34]

You should be able to get rid of the drag lines by changing "combing mode" to "no skin".

It may sometimes not work as the "combing mode" isn't completely bug free, I think.

[gr5 2,268]

Turn off combing for bottom layer.  Combing is a complicated feature and does several things - it should probably be split up into multiple sub-features.  anyway when combing is on you don't get retractions within an "island".

 

To be more exact set "combing mode" to "not in skin".

[mcdavidr 0]

Thank you for the help 

[burtoogle 516]

The "no skin" combing is a crock! I am currently working on a fix for this problem. It's looking promising...

 

Before fix

 

 

After fix

 

[Ricky 5]

Most of the time, combing and z-seam setting from 3.x caused more trouble than improving printing experiences.

 

The paths it generate with different combination of combing and z-seam make non-sense at all.

 

For example, sharpest corner in z-seam. What if there are multiple sharpest corner in the same layer? Such settings should be removed for good.

[mcdavidr 0]

How is the combing fix coming?

[burtoogle 516]

1 hour ago, mcdavidr said:

How is the combing fix coming?

 

It's fixed and a PR (Pull Request) has been submitted - it will get tested by the Cura guardians and if it receives their blessing will be in a future release. If not, it's back to the drawing board!

[mcdavidr 0]

Thank you for your efforts.

[cjs 34]

Thanks @smartavionics for spending time debugging existing features and making Cura more predictable! ? 

[burtoogle 516]

Thanks @cjs. My main reason for spending the number of hours I do working on Cura is to improve the quality of my own prints. The fact that others will benefit too is an added bonus. That is the beauty of open source software. Happy printing!

[kmanstudios 1,120]

On 5/22/2018 at 4:25 PM, Ricky said:

What if there are multiple sharpest corner in the same layer?

Made me laugh in a good way....It is a very good question in IMHO, which is very programming limited.

[burtoogle 516]

6 minutes ago, kmanstudios said:

Made me laugh in a good way....It is a very good question in IMHO, which is very programming limited.

 

The real answer (from looking at the code) is that if a polygon has multiple corners with the same degree of "sharpness", then the first corner found will be chosen for the z-seam position.

 

I don't use the sharpest corner feature much but sometimes it can be quite good. For example if you want to hide the z-seam on a vertical edge that curves, using a combination of sharpest corner and x/y z-seam coordinates, can achieve that. It's not perfect but has its uses.

[Ricky 5]

@kmanstudios

Another option ‘shortest’ is problematic as well. When you define Euclidean distance, you must provide two points. But you have no clue nor control where the starting point of next layer or the exit point of previous layer. In fact, the help options doesn’t even specify what two points are.

 

3.31 Cura parallelize slicing per layer. So you really have no control on two points at all.

 

Another option ‘random’ is horrible, either. Instead to try(not using the word ‘attempt’ here) to solve z seam, you introduced stringy.

 

You always want more control from settings but in reality you control nothing. 

 

I’m always a believer of Occam’s razor principles. I hope you know why now.

 

Edited May 27, 2018 by Ricky