Testers required for "exact" z-seam positioning in Cura development builds

[burtoogle 513]

Hi,

 

I have been working on implementing "exact" z-seams to avoid the rather ragged seams that can occur on curved surfaces.

 

Here's an example: first is how it was before and second is what the experimental code now produces (I have enabled coasting just so that it makes the z-seam location more obvious...

 

 

 

This new implementation is only active when the Z Seam Alignment setting is "User Specified" and the Seam Corner Preference is "None".

 

Before, when those settings were in use, for each layer, it would choose the wall vertex that was closest to the z seam X/Y position to be the location of the z-seam. Unfortunately, the vertices are not guaranteed to align vertically unless the wall has a sharp corner (i.e. with a rectangular shaped wall, you would expect the vertices at the corners for the adjacent layers to be stacked on top of each other) so the seam comes out horribly ragged. Using a finer model mesh and small resolution values help but what it really needs to do is get away from the constraint that the z-seam has to pass through the vertices of the walls.

 

What it now does is take a vertical slice through the model using a plane that passes through the z seam X/Y position and the centre of the model's bounding box and finds where that plane cuts the model's walls and uses that as the z-seam location. Generally, the plane will cut through the model at least twice (goes in one side, comes out the other) and so it chooses the side closest to the z seam X/Y position.

 

If the plane doesn't pass through the model at all, then it just falls back to the previous behaviour of choosing the wall vertex nearest the z seam X/Y position.

 

Makes sense? Well, even if not, I would be grateful if those of you who are using my experimental builds could give this a try some time and let me have some feedback as to whether this is a good scheme or not.

 

Please note that due to a recent change in the build process, if you are using Windows, you must remove any previous installations of my build before installing the current builds. Otherwise, it will not run.

 

As always, my builds can be found at: https://www.dropbox.com/sh/s43vqzmi4d2bqe2/AAADdYdSu9iwcKa0Knqgurm4a?dl=0

 

All feedback is welcome.

 

[Smithy 1,144]

Fantastic idea and great feature! It was always annoying that the seam was not really straight in some models.

Will give it a try the next days.....

[burtoogle 513]

Thanks, I will need to make a MacOS build for you, will do that later today.

[Smithy 1,144]

Don't stress please.....

Thanks! 🙂 

[mtnbkrrick 0]

Is there a way to "paint or draw" a line where the z seam would go? The line could be free hand or orthogonal.  This sounds difficult but figured I would ask.  Nice work!

[burtoogle 513]

1 hour ago, mtnbkrrick said:

Is there a way to "paint or draw" a line where the z seam would go? The line could be free hand or orthogonal.  This sounds difficult but figured I would ask.  Nice work!

 

No there isn't any way to do what you ask and it would be a big job to implement that I should think. It would involve UI programming to do the drawing and then the z-seam contour would have to be passed to the slicer back end which would then work in a similar way to what I have implemented in this recent development.

 

Personally, I would not find it a useful feature because I can't draw a nice line using a mouse so the z-seam would end up at least as wobbly as it is now.

[Dim3nsioneer 557]

While I may have similar issues drawing a straight line with the mouse 😉 it might be a very interesting feature to be able to drag the z seam along the surface of an object starting from a certain xy coordinate on the ground plane. That line might then go up the object in different ways (along x, along y, radially from the center of the build plate, radially from the center of mass, radially from a custom xy coordinate, etc.).

[alexjx 8]

This is really cool feature! I would like to use this. Thank you for bring another great feature.

 

Have you pushed to your github? :)

Edited October 25, 2019 by alexjx

[burtoogle 513]

5 hours ago, alexjx said:

Have you pushed to your github? 🙂

 

Yes, my mb-master branch in CuraEngine contains this feature.

[fufu 0]

Just made this account to post that this feature saved my day! absolutely love it <3 works like a charm.

[mattw 2]

Did this ever get merged into mainline Cura? This would be a useful feature, but I haven't seen any updates in a few years.

[tstone52 0]

Any word on merging this into mainline Cura? I often print things that absolutely need the straight z seam and I'm stuck using this old version of Cura just for those prints. Would be excellent to have this in the new Cura with Arachne.

[NMGMarques 0]

On 7/29/2022 at 8:30 PM, tstone52 said:

Any word on merging this into mainline Cura? I often print things that absolutely need the straight z seam and I'm stuck using this old version of Cura just for those prints. Would be excellent to have this in the new Cura with Arachne.

I'd second this. I am also lost with seams all over the place.

[Arashrk 0]

@burtoogle Wow, thank you so much for this – it works perfectly! The seam line is in a perfectly straight line! I wonder why they haven't implemented this in the latest version of Cura.

[Slashee_the_Cow 265]

32 minutes ago, Arashrk said:

@burtoogle Wow, thank you so much for this – it works perfectly! The seam line is in a perfectly straight line! I wonder why they haven't implemented this in the latest version of Cura.

The Cura devs have a lot on their plate as it is (you just need to look at the number of open issues and pull requests to see that). It would also require @burtoogle (or someone representing them, I guess) to make sure the code doesn't interfere with anything in newer versions of Cura, then push it as a branch into the Cura repo and submit a pull request (which can take quite a long time to get processed, owing to how they're already swamped) to get it added to the main source branch.

 

Short version: Like all software developers, the Cura developers are only human, and they're really busy as it is. And I don't know if it's been submitted to be added, but that also needs to happen, and takes a long time to get processed, because they're really busy.

[Tamadite 0]

I'm on Cura ver. 5.5.0.

 

I'm trying to avoid having the seam near the edges in the following object to not avail despite playing with seam settings. Look at the base of it.

 

 

The object in question is in Thingiverse with name tumstock, link https://www.thingiverse.com/thing:6322311

 

Any hint?

[Slashee_the_Cow 265]

11 hours ago, Tamadite said:

I'm on Cura ver. 5.5.0.

 

I'm trying to avoid having the seam near the edges in the following object to not avail despite playing with seam settings. Look at the base of it.

 

 

The object in question is in Thingiverse with name tumstock, link https://www.thingiverse.com/thing:6322311

 

Any hint?

You could try using @burtoogle's branch to see if that works for you, all I know how to work with is regular Cura though.

 

In regular Cura:

On this model I think it's impossible to avoid it being near the edges because AFAIK you can't make it put a Z seam in the middle of a linear print move, and since the base consists exclusively of rectangles, that means the corners are the only place they can go. You could set Walls > Z Seam Alignment to Random to spread the any imperfections all around, but then you have four slightly messy corners as opposed to one corner with a Z seam.

 

I wouldn't worry about it though - a Z seam on a hard corner is pretty hard to see unless your settings are way off where they should be (in which case the seam running up the model is going to be a real problem.

 

If you use an alignment which will place the whole seam in one corner though, it'll be consistent:

(That's with Alignment = User Specified, Position = Back, Z Seam X = 100 (slightly less than halfway across my 220x220 bed), Corner preference = Hide Seam.)

Edited February 19 by Slashee_the_Cow

[PartySausage 13]

It would be really good if this was integral to the official Cura releases, sometimes I can't get my z seam where I want it 

[Slashee_the_Cow 265]

56 minutes ago, PartySausage said:

It would be really good if this was integral to the official Cura releases, sometimes I can't get my z seam where I want it 

The feature request form is here, just search to see if there's an existing request first which you can +1 because it's annoying for developers to have to find the existing one and mark yours as a duplicate because I'd be very surprised if you were the first person who'd like to see this integrated into mainline Cura.

[Tamadite 0]

13 hours ago, Slashee_the_Cow said:

I wouldn't worry about it though - a Z seam on a hard corner is pretty hard to see unless your settings are way off where they should be (in which case the seam running up the model is going to be a real problem.

Thank you very much for your supporting answer!

 

The problem behind this case comes from a combination of PETG filament and overhangs. PETG does not like fan cooling and because of its elasticity the overhanging corner drags up with the seam when the Z lifts. This leads to noticeable imperfections and a higher risk of having the nozzle knocking off the object.

[Slashee_the_Cow 265]

8 hours ago, Tamadite said:

The problem behind this case comes from a combination of PETG filament and overhangs. PETG does not like fan cooling and because of its elasticity the overhanging corner drags up with the seam when the Z lifts. This leads to noticeable imperfections and a higher risk of having the nozzle knocking off the object.

I always run PETG with the fan at 100% (although effectiveness can depend on printer). It's a stringy material (It's hard to say that with a straight face when you've printed as much TPU as I have) and the faster it sets (by cooling) the less likely it is to travel off with the head instead of staying put.

 

If you're printing PETG remember that it doesn't print as fast as PLA (I usually run it at about 40mm/s) and if you have one of the speed demon printers you can get these days (like my Ender-3 V3 SE which can accelerate at up to 4000mm/s²) it's worth lowering the acceleration rate, including the travel rate. I've seen my printer yank parts of PLA with it as it's gone zooming off on a travel move and end up stretching the model in that area.