Ironing despite 0 Top Layers

[ameuret]

Application version
4.7.0

Platform
Linux

Printer
Custom (Monoprice Select Mini)

Reproduction steps

1. Add model
2. Add mesh modifier model (for overlaps and cutting mesh)
3. Set mesh modifier setting for Top Layers (and Bottom Layers) to 0
4. Enable Ironing (in general settings, not modifier mesh settings)
5. Slice and observe that an ironing pass is generated on unexisting top layer

I checked that when disabling the general Enable Ironing setting, the spurious pass disappears.

Screenshot(s)

Actual results
Ironing pass is generated.

Expected results
No ironing pass when no layer to iron exists.

Project file
https://groupeactime-my.sharepoint.com/:u:/g/personal/arnaud_actime_biz/EcxK6WZSgddBvNyVxsksaCcBfdVV_pq_8sqBdMQlYonsTw?e=8Icew0

[rburema]

Also doesn't work the other way around (ironing on for modifier mesh, ironing off in general).

[Malmik]

Cura 4.8, cartesianXY
Just experienced this:
(You can see that there IS NO top layer, while there IS ironing, becouse you can look throught the ironing)

[MalicT]

Just had this happen with mine too, was doing a 2 wall box for calibration of flow, with 0 top layers, because of ironing option being checked had it try to do a top layer, took a bit to figure what was causing this

[Ghostkeeper]

Shouldn't you then, like, disable ironing instead?

Ironing doesn't specify that it only works on skin layers. In fact, it normally goes over all of the walls and infill too. That's part of what makes it smooth out the surface well.

[MalicT]

that is the point of the bug report, it should disable trying to iron a layer that does not exist, it should only iron the tops of the walls, not try to do the entire flat area, since top layer was set to 0

[tastyratz]

I noticed this recently and it seems like it's still happening. If Ironing is left on it will iron the top phantom layer, not calculated/actual layer.

Even when you set iron only highest layer it will try and iron the top of the object as it thinks that's the topmost layer. This makes ironing objects printed without a top for use as a vase impossible. Cura tells the printer to try and iron with nothing there and the slight extrusion for ironing makes a mess of the top of the part at the end.

[MariMakes]

We've added a ticket to the backlog to improve this.
For internal reference CURA-10271

Thanks for the report! 👍

[daniels220]

I would add that disabling ironing for an area of skin that does exist, using an infill mesh, also doesn't work, and there's no reason for it not to. Using a cutting mesh allows it to work, but generates spurious outer walls when trying to affect only part of a layer.

[GregValiant]

Is this still an issue in current versions of Cura (5.8.0 and up)? Can this be closed?

[daniels220]

The behavior seems to be unchanged, that is, Cura will iron wherever the model is present, even if no top layer is present. This is true regardless of whether modifier meshes are involved, and conversely, using a cutting mesh to disable ironing altogether works properly—you can disable ironing across only part of the model this way. However, this means that the boundary between ironing/no ironing will always have a wall, and this wall cannot be made any thinner than the outside walls of the part as a whole (you could try by introducing another modifier mesh but this then introduces its own wall). So this is pretty limiting.