I noticed these extremely weird behaviors of Cura

[Neukyhm 2]

I noticed 2 very weird things Cura does, let's go with the first one.

 

First thing

This is a very simple box I'm making for a machine, see the picture, Cura makes the printer perform a travel through the box. The blue line is what it does, the red line is a shorter and faster path that avoids that travel. It's not that it wastes much time doing that travel, but multiply it for hundreds of layers. The thing is that when Cura finishes slicing an island of the layer, instead of going to the nearest island it goes to the other corner of the box.

 

Second thing

With the same box, I have noticed that ALL layers start at the same corner of the box. This simple thing adds new travels when the printer could just start the new layer at the same point where the previous one was finished. And yes, I have tweaked Z Seam alignment  to shortest, random, etc, nothing changed. I really find this very weird, why traveling to a new position to start a layer when you can start it at the point the other layer was finished?

 

Thank you in advance guys, I really want to adjust everything to get the fastest print, because this box is really big and Cura is telling me already times of 25 hours of printing.

 

 

Edited September 30, 2018 by Neukyhm

[smartavionics 289]

Hello @Neukyhm, the second thing (layers start at same corner of box) is a constraint that came along when Cura's slicing engine moved from being single threaded to multi-threaded. Now it is multi-threaded, all layers start at the same location. Arguably, that is a regression but that's progress for you.

[Smithy 457]

So that means, it is irrelevant what we set for Z-seam alignment?

[smartavionics 289]

15 minutes ago, Smithy said:

So that means, it is irrelevant what we set for Z-seam alignment?

No, z-seam alignment settings will still have an influence as before but the difference is that now it will no longer start a new layer where the previous layer finished when z-seam is set to closest.

[Neukyhm 2]

1 hour ago, smartavionics said:

Hello @Neukyhm, the second thing (layers start at same corner of box) is a constraint that came along when Cura's slicing engine moved from being single threaded to multi-threaded. Now it is multi-threaded, all layers start at the same location. Arguably, that is a regression but that's progress for you.

Multithreading is a very useful feature, it makes slicing faster, but sometimes (like in this case) I prefer a longer slicing time if I can save an hour or more in a 25h print.

[smartavionics 289]

I agree that it would be good if you could choose between faster slicing and better quality output.

[Neukyhm 2]

1 hour ago, smartavionics said:

I agree that it would be good if you could choose between faster slicing and better quality output.

I agree too. I have tested an object using Cura 3.4.1 and Cura 2.3.1. The result is that Cura 2.3.1 does a faster printing:

 

This is the test object:

 

This is the slicing in Cura 3.4.1, you can see that there are 2 travels for each layer (printing time 9h26m):

 

And this is the slicing using Cura 2.3.1, only 1 travel per layer because it's starting every layer where the previous one was finished):

 

The result is that Cura 2.3.1 is faster at printing, the difference is not very high but this was only a test object. More complex objects could have a bigger print time difference.

 

[smartavionics 289]

Yes, but it is how it is. We have to live with the current behaviour. You can open an issue on github and complain about it but I doubt if it will get acted upon.

[Neukyhm 2]

2 hours ago, smartavionics said:

Yes, but it is how it is. We have to live with the current behaviour. You can open an issue on github and complain about it but I doubt if it will get acted upon.

And what about the first thing I noticed, it is really strange that Cura will travel to a far island when it has others nearby. I have already posted the issue.

Let's see what people on Github do.

Edited September 30, 2018 by Neukyhm