Taz 6 w/Cura printing like a photo negative

I am trying to print a Sketchup drawn piece that I have printed before I made slight modifications. It is printing holes, and leaving open the solid areas, just like a photo negative. I reverted to suggested settings with no luck. I have re-loaded the drawing, but have no other ideas of how to correct this. Ideas?

Thank you!

Sketchup is not designed for 3D printing, and is not based on solid modeling. This basic software design choice can make ambiguous geometry that is left open (no pun intended) for the slicer to interpret how to close the surfaces to make a solid. The 3D rendering engine and slicing engine can sometimes have very different interpretations of geometry when it’s not fully enclosed.

Using a solid-geometry based modeling program like OnShape or TinkerCad (OnShape is my software of choice for a free solution) is my recommendation. If you can share the source files you’re working with I can see if there’s a simple fix for the files, but generally, editing files with Sketchup is not something you want to get in the habit of doing. Yes, it’s easy to learn, but I can guarantee you that once you put a couple hours into basic OnShape tutorials, you will be saving time and frustration over Sketchup.

I have not heard anyone explain the software issues like that, but it does make sense. I have been using Sketchup for several years now, and there have been some frustrating issues with minute gaps that are hard to find, but that leave the drawing unprintable until repaired. I will definitely explore the alternatives you suggested.
That being said, I am not yet convinced that is the issue here. The print is not being attempted as if there are gaps, or the printer is trying to print an open object. It truly is trying to print the opposite of what is intended. It is leaving three little cylinders where the mounting holes should be, and a slab where an opening should appear.
I am not sure if the STL will help any, so please let me know if there is a format the I can convert the skp to that would.
Vanometer Mount 1-3-3.stl (52.7 KB)

Thank you so much!

Yes, one sided geometry and open sides all over in this.

Looks pretty painful to make in the free version of SketchUp, but a 5 min job or less in onshape (on my pc, not on my phone).

I was just getting ready to reply back to you and retract my comments. I saw the flaws as soon as I opened it up, and I’ve already been dabbling in OnShape. Thank you for the advice!

Edit: Part of this that makes it painful it that I have Sketchup pro, and have gotten fairly comfortable with it… :frowning:

Edit II: I altered the original drawing, needing to taper parts of it. That’s where things went downhill fast, and I missed catching all of the flaws.

I’d been using SketchUp for a while before I switched over. There was about a week where I’d get frustrated just trying to rotate or move an object before I had made the mental transition to the better way. Start with Teaching Tech’s series for OnShape, but big thing is not to build bad habits trying to figure things out on your own… you’ll learn complicated ways of doing things you probably figured out by using more limited CAD programs instead of the simple way by just using an extension people have made (SurfaceText, Attractor Pattern, and Fill Pattern to name a few).

Here’s a rebuilt STL file, and a link to the file on OnShape:

Vanometer Mount 1-3-3.stl (140.5 KB)

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Here’s a CAD program the works for me.

Thank you for the suggestion, Mike. I work for a hospital network that is in its infancy with 3D printing, so I will probably try OnShape for now (due to pricing), but I will definitely look into this!

Shap3r’s limitation on designs (two!) really limits free use for me. But then, OnShape’s making any free tier user’s files available for read-only is probably a bit limiting for others.

There’s also freeCAD, but I really do like the cloud-based solutions.

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Apparently, I have not found all of the flaws in this… Can anyone lend a hand? I’m at a loss… Also, what program do you use to edit an STL file?

Thank you!

Vanometer Mount.stl (30.2 KB)


If the .stl file has manifold errors, you can usually fix them with MeshMixer. Click the left side icon Analysis, choose Inspector, and then Auto Repair All.

There are other tools / slicers that can repair these types of errors but this is the one I use most often.

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So I remade it completely from scratch and it’s like a cursed shape that refuses to slice correctly in Cura, but slices perfect in PrusaSlicer.

Thank you for the advice. I will look into it.

Thank you so much for all of your effort! I will try to simplify the design and redraw from scratch as well. It takes an act of congress to get new software approved for our network.

So the model you made in SketchUp had flaws, but the re-made one I did wasn’t. I can’t explain the exact reasoning, but I felt like the simplicity was working against it, so I added a simple small small fillet to some of the edges around the problematic hole, so that Cura would see more a change, and it worked in CuraLE:

Vanometer Mount 1-3-3 - Part 2f.stl (125.9 KB)

That’s awesome! Thanks so much! Just so I can learn more, is it possible to easily describe where these flaws are?
I have redrawn it as attached - hopefully with less flaws. I will try printing this one, as well as yours.

Thanks again!
Vaneometer Mount 1-4-2.stl (46.1 KB)

Not knowing your workflow for producing it, I can’t say what caused them, but the flaws were open sides and some flipped faces. Since SketchUp colors the inside and outside faces so closely together, it can be nearly impossible to tell the inside and outsides apart. With a solid modeling program, any face you can see is the outside. The only way to see “inside” is to use a section view, where the interior shows up filled.

Your 1-4-2 version slices fine for me:

The only tricky part will be printing the overhang up near the top.