Cura 5.x Spiralize Mode Broken

[stampydriver 0]

In Cura 4.x the attached file printed out great. After upgrading to Cura 5.x it is no longer possible to print the attached file. Screenshot attached with the result of the slicing. It is better with surface mode set to just Surface, but the horizontal surfaces are then not printed.

 

 

Ikea LED Lampshade v4.obj

[stampydriver 0]

In addition since 5.x the spiralize feature seems to generate a double wall when it should just be sprializing the outer wall.

[GregValiant 1,251]

If the model isn't solid through-and-through then spiralize will print the outer wall that is facing outwards, and the outer wall that is facing inwards.  That is not what you are looking for but Cura is trying to print the model you have open.

 

You can enable the Mesh Fixes setting "Remove All Holes" to make the model solid so it has a single exterior surface.  That will allow spiralize to work.

There have also been complaints about the bottom layer pattern in Spiralize.  There is only one option now and it is "concentric".  There has been a bug report opened on GitHub regarding that.

[stampydriver 0]

Indeed the Remove All Holes setting fixed the double wall and the spiky interior, but the bottom is now solid where there should have been a lip.

 

 

[GregValiant 1,251]

You might have to go back to 4.13 to fix that.  I've tried before and didn't find a way to put a hole in the bottom of a spiralized print.

[Kazymandias 0]

On 8/1/2022 at 5:38 PM, stampydriver said:

Indeed the Remove All Holes setting fixed the double wall and the spiky interior

Well, but it's still not actually vase mode, right? It's both walls but with a solid interior. Spiralize is still not just doing the entire print in a single spiral upward, is it?

 

I have a print that is also behaving insanely in spiralize mode. Two walls and a ton of travel across the print. Making it solid won't make it quickly print a single spiral up...it will still break the spiral to do both walls and the solid infill, and presumably whatever the effing path is that this is doing. Which is causing a web of stringing in my TPU print. I didn't expect to need to tweak the settings to avoid stringing, given that it's supposedly spiralized.

 

The strangest part is that I did another model from the same thingiverse posting just a couple of months ago, and as far as I can tell it printed spiralize (in PLA) perfectly, no double walls and no ruined spiral. I don't think I've upgraded Cura since then. 

 

Edited September 22, 2022 by Kazymandias

[GregValiant 1,251]

Here we have a tale of two models that were identical until I put a hole through the one on the right.

The model on the left is suitable for Spiralize.  The model on the left is not.

 

Spiralize is enabled.

Left model sliced.

 

Right model sliced.

 

Comparing the two gcode files, the gcode shows that both models are spiralized and on each layer (above the base layers) the Z gradually increases until the nozzle is back to the XY layer start.  At that point it is one layer height above the previous XY layer start.

The difference is that the path of the model with the hole must cross over the empty space in order to do the wall of the hole.  All of that is part of the path and so there is an extrusion from the outside to the inside.  When the inside is finished the extrusion ends and there is a travel move back to the outside at which point it is one layer height above the previous XY start.

What else can it do?  Essentially once the bottom layers have printed there are two islands.  One is the inner bore and the other is the outside of the model.  The nozzle has to move from one island to the other and then back.  One way the nozzle is extruding (as that portion of the path requires) and after finishing the extrusion portion of the path it travels back to the layer start point.  The result will be a seam on the wall of the inner bore and a seam on the outer wall.

 

In this model I've added a slot .1mm wide that goes from the outside to the bore.  This model will truly spiralize but there will be a wall (it will look like a double wall) because of the slot.  You can see that there are no travel moves and other than the scar of the slot, there is no seam.

 

Some models just aren't suitable to be spiralized.  Models with holes won't work whether the holes are vertical or horizontal.  You cannot have more than one model on the build plate when spiralize is enabled as you have two islands and the same problem arises and both models will have seams.