Random lines appearing in Cura spiral mode

[ethanchild45 0]

I am currently trying to print this Fractal Pyramid in spiral mode but when I slice it and look at it in preview mode I see random lines on the 15th and 134th layer. Any suggestions on how to fix? 

[GregValiant 1,112]

Most fractal pyramids I've seen have layers that have "islands" on them.  When there are islands the print head has to move from the feature it was printing, across an open space (extruding all the way), and then print the next feature.  It then does a travel move back to the original feature and starts the next layer.  Models with islands can't really be spiralized  because by definition the extrusion should be one continuous extruston from the bottom to the top and with islands it just can't be so.  Those lines you see aren't "random" at all but part of a spiral path that has to move from one area to an island.

Since it sounds like it's only happening on a couple of layers there may be slight errors within the model that don't get connected.  You could try increasing the layer height setting in Cura, or scale the model down in the Z.  

[MakerWerks 0]

It's May 2023 and the same problem exists. I have to go back to Cura 4.x to properly do spiralized print. This is pretty frustrating.

[GregValiant 1,112]

Please understand that I don't work for Ultimaker nor do I own an Ultimaker printer.  I do use Cura.

It seems to me that the 4.x versions accomplished spiralize on certain models by ignoring some of the geometry.  The 5.x versions do not.

Consider this model.

 

In 4.13.1 it spiralizes like this and has a hole in the bottom, but where is the tube that should come up the center?

 

The same model sliced in 5.3.1 doesn't have the hole because by default when you turn on Spiralize you automatically enable "Remove all Holes".

 

But if you turn off Remove all Holes you get the mess BUT the inside tube that is part of the model geometry prints.

 

So if I want this model to be like 4.x would print it (with the hole in the bottom) then I have to make an adjustment.

 

There are things you can do but certain models just aren't suitable for spiralize.  In my estimation the best spiralize is the Smart Avionics fork of Cura.  It's based on the 4.x versions of UM Cura and along with some other fixes it adjusts the flow of the first spiral layer to get rid of the hump that UM Cura puts into the print.

I own about 10 hammers.  They are all different and I use the one suited to the job.

If you print a lot of models using spiralize then you need to pick the best tool.  If you don't feel you are getting what you want from the UM 5.x versions then yes...use another.  At some point the Cura team will slow down from putting out the fires and have time to assess things like the spiralize behavior.  They may not change it, but I'm confident they will look at it.