solid bodies are hollow - .stl / 3d printing errors

[hkbarnes]

I'm totally new to CAD and design so I apologize if this is a stupid question, but I've been working on this for a while and can't seem to figure out where I went wrong. I have a basic part design which is built mostly from extrusions and extrusion cuts.

Everything looks normal, but when I threw the STL in Cura only the horizontal surfaces of most of the part are recognized. When I analyze the part with the half section view I can see that most of the extrusions appear hollow inside. When I flip the .stl 90 degrees in Cura, it again doesn't recognize the part as fully solid.

I'm going to try and attach my files. Hopefully someone can tell me what I did wrong, and how to avoid this in the future.

Thanks

[hkbarnes]

More screenshots to explain how it looks in a slicer.

   

[Gabriel_Watson]

Can you attach your STL export? I think this is simple though: STL files are mesh-based, and may not be interpreted as solid geometry anymore, so you might want to use another file format such as STP or Parasolid if Cura can open those.

[hkbarnes]

I haven't tried that one yet, but I'll give it a shot. I'll also upload the .stl later for everyone to see.

I do believe the error is with the design or a setting I mistakenly clicked somewhere. If notice from the cross section view in Inventor, a couple parts do appear solid, those never have the same issue when the .stl is imported. The other pieces of the solid body are hollow and they show up as just the horizontal surfaces.

[Gabriel_Watson]

I exported here using Inventor 2022.2, and imported back just fine. I'm attaching my STL created from your IPT so you can test importing there to see how it is read on Cura.
I think you might want to play with the options on the export window to see if you can find a better custom setting too:

[mcgyvr · Accepted solution]

@hkbarnes  "Shell 1" caused your "solids" to become hollow. 

Use another extrusion (with the "cut" option) to clear out that USB jack instead.

(or edit Extrusion 8 and check the "new solid" option to allow you to only select the USB solid to apply the shell too..)

[hkbarnes]

Galaxybane -

Thanks for the reply!

I tried some of the suggestions on the .stl and it didn't make a difference when I brought it to Cura. Cura unfortunately doesn't take in .stp files either. The problem is something in my design or settings.

I tried the .stl you provided but you set it to centimeters instead of milimeters so it was so small I couldn't tell if that one would have worked either.

[hkbarnes]

mcgyvr -

Thanks! this was definitely the source of my issue. I made some of the recommended changes and it fixed most of it. Now I still have a couple bodies that are missing vertical surfaces / areas when sliced in Cura. I'll attach my files again. I hope you have time to take a look.

The Cura screenshots - pre and post slice

https://imgur.com/a/MuHZuv5 

The other odd issue, is when I try to use extrude on any existing surface, they won't highlight/preview. It wasn't doing this before. I'm not sure how I broke this so bad. 😕

[mcgyvr · Accepted solution]

---

@hkbarnes wrote:

mcgyvr -

Thanks! this was definitely the source of my issue. I made some of the recommended changes and it fixed most of it. Now I still have a couple bodies that are missing vertical surfaces / areas when sliced in Cura. I'll attach my files again. I hope you have time to take a look.

The Cura screenshots - pre and post slice

https://imgur.com/a/MuHZuv5 

The other odd issue, is when I try to use extrude on any existing surface, they won't highlight/preview. It wasn't doing this before. I'm not sure how I broke this so bad. 😕

---

@hkbarnes Those verticals are thinner than your machine/settings can print. 

You also have areas like the SD card, USB jack and (I'll assume ribbon cable connector) that won't print properly either without supports. A 3d printer can't just print in thin air. 

[hkbarnes]

This was it. After I resolved my design errors I kept banging my head against the wall wonder why it renders so weird in the slicer. Bottom line is that I had surfaces that were thinner than the minimum extrusion so it just wasn't possible. This is obvious after I figured it out.

I was only wanting to print it for fun to see how close the model was to the sample.

Thanks again for the help!