Baffling Cura problem printing "Corrugated" shed

Hello Hive Mind,

I’ve run into a bizzare problem I can’t resolve. I’ve tried two versions of Cura for this (4.8 and 3.1) and both do the same. I haven’t done anything with Prusa yet because I’m so deep into this project that I don’t want to have to learn anything new at this stage of the game.

One element of the model I’m making involves a corrugated steel shed. It’s a pity I can’t upload the STL.

On my initial test print, I printed it in super quality and it took an hour, but the slanted roof was kind of ugly, so I thought I’d re-position it on it’s roof, on a raft and, given that the angle is only 15 degrees, it shouldn’t need supports on the walls. I figured that would cut down on the print time since the 1hr print had internal supports under the roof.

Now, when I slice it, I just get the roof on a raft.

Positioning it in this orientation…

Yields this mess when you slice it. As an added bonus, the number of layers shown, when multiplied by the .2mm layer height comes to the actual height of the shed and clearly this puddle isn’t that tall.

And yet this orientation printed fine.

The walls of the shed could be too thin.
At vertical they can build on one another yet even at the 15 degree angle they don’t.


The walls are .3mm. When standing, the roof printed at 15deg from horizontal and yet it printed fine. There were stringing issues across the tops of the corrugations which is why I decided to re-position it. When I position it on it’s roof, the walls will now be at 75deg from horizontal and that should easily be printable. That would mean that the layer shifts by only .29mm from a .4mm nozzle which gives plenty of overlap so I should think Cura would have handled it.

I made the entire project in OpenSCAD as a parametric model, so changing the wall thickness is no problem. I’ll take your suggestion and increase the wall thickness and see what happens. The wall thickness was chosen to simulate a 1" thick wall, which, for corrugated steel, is much thicker than prototype. I didn’t want to make it too thick or it starts to look unrealistic.

Although now that I look at it, the standard test extrusion test cube prints walls that are .4mm thick, so .3 might have been pushing it. But then again, I did successfully print an upright prototype. Sooooo… off to test your theory…

The roof would print fine because it had supports for it, no supports for inverted shed and walls.
I have to scale down most of the things I print for works and have to adjust thickness of material in actual to be at least 1mm ( my preference) in scaled down print.

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You are indeed correct. .4mm is the magic number, and yes, I completely forgot about the fact that I was supporting the roof. .4mm shouldn’t look that abnormally thick. It’s a control shed that goes on the end of a railroad turntable, b.t.w.

Thanks for the help. I’m going to print it and see how it turns out.

I figured it was for model railroads, I do some for a colleague at work. For him mainly rail car bodies and shipping containers.

I use a design guideline from 3D hubs. Min recommended wall thickness is FDM 0.8 mm and 0.5 for resin. Seems to work for me. My ender 3 has made some amazing models for my n scale railroad but I also bought a resin printer for small detail items. :grinning:. Resin brought other fun as some resins like to warp after printing​:open_mouth:


Have you tried setting the “Print Thin Walls” option – found in SHELL in Cura 4.8, and in the new WALLS in Cura 4.9 This solved a problem I was recently having with printing N Scale RR items.

THANK YOU! I had solved this problem shortly after posting the thread but couldn’t remember how I did it. Yesterday, I was trying something else (lettering) that was pushing the boundries and for the life of me I couldn’t remember the Print Thin Walls setting. I somehow kept missing it. Drove me nuts.

I often run into issues when scaling down items for my n scale layout which were designed for other scales and this has helped a number of times. I just leave it turned on permanently these days as most of my recent printing has been for the rr.