How to make this thingiverse box 'watertight'?

[terrypin 3]

I downloaded this Arduino box from thingiverse

 

https://www.thingiverse.com/thing:994827

 

and loaded this STL into Cura

 

https://www.dropbox.com/s/0es0o1o356b2aw3/arduino_uno_bottom.stl?raw=1

 

 

 

But it gave the message "not watertight and may not print properly". I couldn't see anything obvious in Preview (although as a novice that's not surprising!) so I went ahead anyway. Sure enough, turned my back on it for 10 minutes or so after a while and got a tangled mess, dragging around the apparently finished (but flawed?) rectangular base.

 

Thought I'd use this as opportunity to try the Mesh Tools extension. First tried 'Fix simple holes' which gave "The mesh needs more extensive repair to become watertight". Then used 'Fix model normals', which didn't report anything. Should it? I sliced it again but the resulting gcode was identical to the original in size, so presumably nothing has changed. In short, I'm lost. How should I now proceed please?

Terry

0 comments

 

 

 

 

 

 

[GregValiant 1,251]

I've got a system for bad models.

If Cura complains about an STL, I check it and analyze it with the Mesh Tools.  This didn't tell me anything other than "Not Watertight.

Then I start IdeaMaker and load the STL.  In my opinion it has better mesh repair tools.  That didn't tell me anything either and in fact didn't find any errors with the model.  That was a clue.

Next, I upload to Service.NetFabb.com and so far there has only been one model I uploaded that it couldn't repair.  In this case it did repair the file but as is typical, it didn't tell me what was actually wrong with it.

So I used MS 3D builder.  It also repaired the file but didn't tell me what was wrong.

My final check is to slice the bad model and the repaired model side by side (if possible) and look for differences.  This time I didn't see any.

So my opinion (keeping in mind that I'm only on the Junior Varsity here) is that there ain't much wrong with it.

Attached is the repaired file.  In this instance I think the original file would have sliced fine.

arduino_uno_bottom_fixed.stl

[kmanstudios 1,120]

I ran the original file from dropbox through 3DS MAX and did the STL check....it found no errors. Then I loaded it into Cura 4.8 (I have not upgraded since I saw a bit of chatter about issues with it) and got no error when loading or slicing. What version of Cura gave the error?

[GregValiant 1,251]

4.10 beta for me.

[kmanstudios 1,120]

That is good to know for the devs. It is either an error that needs to be addressed or maybe a change in how it evaluates models. I can say that the STL Check in 3DS MAX is always spot on for checking and letting you know what errors there are.

[GregValiant 1,251]

Yea, I should have mentioned it.

From the bottom, Meshmixer shows all four through holes of the original file like this.  When I load the "repaired" file it looks the same to me.  It's apparent that there is a gap in my knowledge that a truck could drive through.

 

 

This is after using the "Make Solid" tool in Meshmixer.  I'll reserve additional comment because it appears it could be a really big truck.

Edited July 6, 2021 by GregValiant

[kmanstudios 1,120]

What you are seeing is the same model that in the first picture has not been 'smoothed'. The second image shows the same geometry, but with smoothing applied. That is why the hard angles look 'rounded'.

 

Smoothing is just an algorithm that causes the geometry to look good without the oddball geometry being noticeable. If the walls had a different smoothing on the bottom as from the walls, you would see sharp corners on the meeting of the walls and bottom 'planes'. They are not true planes. Just a collection of triangles.

 

If one was to take it to the next layer, smoothing values on all the major surfaces, you could make it look hard edged. It is just a visual bit of trickery. The same way a low res cylinder looks smooth in the slicer view port, but will still print with facets.

 

    Make sense?

[GregValiant 1,251]

You always make sense sir.  The question is whether I understand what you are saying.  In this case I think I've hit a snag.  As I rotated the model around and stared at those triangles that make up the areas around the holes, they just looked "wrong".  3D builder seemed to indicate that the errors it found related to the bottom surface of the model.  

 

It would be nice to find a software that could look at an stl and tell me what exactly is wrong.  Netfabb tells me nothing.  Ideamaker has it's stats window that I like (but in this case didn't see any errors to report on).  3D builder and Meshmixer are not intuitive and just tell me "something" is wrong and then that it was fixed, but there is no analysis.  Cura's mesh tools are OK when viewed with the rest of the group.  When looking at the lot of them with a view at their Mesh Analysis Tools the phrase "mediocre at best" seems to apply to the entire group.

[terrypin 3]

Thanks for all the responses.

 

After a few hours further research I discovered that great tool in 3D Builder, which confirmed there was a problem and fixed it. But, as Greg says, without explanation of the cause. (Although I doubt it would have meant much to me as a beginner.)

 

Before that discovery I'd unsuccessfully installed Mesh Tools and tried the two tools there in vain. Then I brazenly tried two prints. Both failed. I didn't catch the second until maybe an hour into a 1h49m print, and by then the base of the case was sliding around beneath a tangled mess.

 

After the repair by 3D Builder I reloaded it into Cura (4.91) and printed it. Followed the same routine with the top of the box. I do so wish Cura could include such a terrific tool.

 

Terry

 

 

 

 

 

 

 

[GregValiant 1,251]

In regards to adding more or different tool functionality to Cura, this comes up once in a while from the SolidWorks/Inventor/Fusion360 crowds.  Cura should be more capable dealing with the models and making adjustments to models or Cura should be tied right in with the CAD software so all an operator needs to do is think about slicing the parts and wham - done, or Cura should have assembly capability, and on and on it goes.

I have numerous toolboxes and they each have a specialty.  I don't do plumbing with the electrical tools.  I don't drive nails with a crescent wrench.  Each tool is good at what it does.  Cura is good at what it does.  If a bunch of sideline capability were added what energy would the team have left to keep Cura at the top of the heap of slicers?  Let it be the best slicer that the team can come up with.  I've got other good tools for other tasks and "they're only a click away".

 

"Universal means it won't work either way" - Dick Mara (RIP)

[terrypin 3]

What I should have said was "I do so wish Cura and its extensions/add-ons could include such a terrific tool" As mentioned, I used two 'Mesh Tools'. Neither 'Fix simple holes' or 'Fix model normals' fixed my two STLs.  Happily, the 3D Builder tool did.

 

 

 

[kmanstudios 1,120]

16 hours ago, GregValiant said:

It would be nice to find a software that could look at an stl and tell me what exactly is wrong.

See if you can find an old version of 3DS MAX. It has an STL Check that will do just that. The triangles look wonky because it probably came from a program that booleaned the surfaces and that always makes wonky triangles.

 

13 hours ago, terrypin said:

which confirmed there was a problem and fixed it.

I beg to differ just because I could get a good slice out of Cura 4.8 and I have never had any issues coming out of my software.

 

This is the bottom of my slice

 

Full Slice

 

I am running a test, but from what I see, all is good.

What machine are you printing from?

[terrypin 3]

I'm using the latest general version 4.9.1.

 

As you don't get the 'not watertight' message I'm wondering if I did post the original version. Just in case, I've downloaded it again and still get the same behaviour, Here's the file once more:

https://www.dropbox.com/s/766koetnivd9la4/arduino_uno_bottom.stl?raw=1

 

I too thought it looked good, although to be honest at this stage of learning I don't know what I'm looking for. In the following screenshots the only 'odd' things are the tiny white bits, which the colour legend says are 'starts'. Are they a relevant sign?

 

 

 

Nor did the recommended X-ray view tell me anything. What am I looking for in that?

Needless to say I did not again print from this original, given the mess it caused before:

 

 

The top part of the case gave the same problem. Here's its file:

 

https://www.dropbox.com/s/ttzhlxtw74i8syf/arduino_uno_top.stl?raw=1

 

To repeat, I wish Cura (or its Extensions) had such a handy tool as 3D Builder. As an end user with 3D printing as a new hobby, I just want to get files printable 😉

 

Here's what the finished two parts look like after being fixed:

 

 

Terry

 

Edited July 7, 2021 by terrypin

[kmanstudios 1,120]

I went back to your original post (the thingiverse link) and got the original file. Unzipped it and got rid of old file. This pic is 3DS MAX's STL check utility in action. The top square is for isolating errors it may find. Here it is showing that it is displaying what it found in the "everything" category. The bottom square is showing no errors on everything.

 

This is the same file sliced as before.

 

I am printing a test out and so far, it is spot on.

 

What printer are you using? This was sliced using an S5 (r1) printer. I agree that the utilities you mentioned should give you feedback of some sort. But I am wondering if the issues may be related to printer definition other than UM printer. Also what material are you printing with?

 

Will post pics of print in about 15 minutes when it finishes.

 

Edit. Just checked and sliced the top separately. Got the same results. When you sliced the top, did you flip it to the flat side with sides printing upwards like so?

Edited July 7, 2021 by kmanstudios

[kmanstudios 1,120]

This is the print that just finished. I slammed it through at the fastest speed and largest layer size. Was not worried about being pretty.

 

[terrypin 3]

Quote

This pic is 3DS MAX's STL check utility in action. The top square is for isolating errors it may find. Here it is showing that it is displaying what it found in the "everything" category. The bottom square is showing no errors on everything.

 

Thanks but I don't want to install and learn yet another program! But out of curiosity where in that image does it tell you there are no problems, i.e. it is 'manifold' or 'watertight'?

 

Quote

What printer are you using? This was sliced using an S5 (r1) printer. I agree that the utilities you mentioned should give you feedback of some sort. But I am wondering if the issues may be related to printer definition other than UM printer. Also what material are you printing with?

 Mine is Ender 3 V2, using PLA. You could be onto something about 'printer definition'. I'm just about to post a new question about printer settings.

 

Bottom line: are you confirming that in Cura (4.9.1), for some reason you don't get the error message opening the original STL?

Edited July 7, 2021 by terrypin

[kmanstudios 1,120]

25 minutes ago, terrypin said:

Thanks but I don't want to install and learn yet another program!

Did not think you would. I was just explaining the process. If the utilities do upgrade to provide such information, it should be something like what I showed. Not just generic "Not manifold" or such.

 

25 minutes ago, terrypin said:

But out of curiosity where in that image does it tell you there are no problems, i.e. it is 'manifold' or 'watertight'?

It checks for everything. If not manifold, it will throw an error. Usually open edges or vertices. That is what creates the 'holes'.

26 minutes ago, terrypin said:

Bottom line: are you confirming that in Cura (4.9.1), for some reason you don't get the error message opening the original STL?

Nope. I opened in 4.8. I have seen too many issues for me to upgrade and deal with oddities. I am not as swift on tech problems as I used to be. I just lean towards the issue possibly being printer definition is because both you and Greg use a printer type that is non-UM. That is a whole other can of worms that I am totally ignorant about.

 

[terrypin 3]

What is a UM printer?

 

Anyone else tried the original file in 4.9.1, to eliminate version as a cause?

 

Edited July 7, 2021 by terrypin

[GregValiant 1,251]

@terrypin - First I'll apologize.  Kman and I tend to let our curiosity get the best of us, then we are talking over people.  Sorry.

UM is Ultimaker and my printer is an Ender 3 Pro.  There is nothing in a printer definition file that would cause Cura to slice something differently for one printer than another.  Now Settings Profiles and Material Profiles are a different story and they can vary by printer.  Ultimaker's are much more precise and robust than my Creality machine and so Profiles for their printers are both more aggressive (speed and acceleration) and designed take advantage of the higher precision.

 

I just opened the original file in 4.9.1 and it is the same as Kman saw in 4.8 and that you and I saw in 4.10.  There is a little blip of an error in the STL.  It isn't enough to have an effect on this particular model and as Kman shows - it prints fine.

 

So have at it.  Whatever caused your spaghetti problem wasn't the error in the model.

[terrypin 3]

Thanks, understood.

 

But two successive failures at what seems the same place/time seems fairly conclusive to me! So don't want to risk trying another print. As you saw, I have now already finished the project so after the 3d Builder fix. Took a total of about 3 hours for the two parts. And about 5 hours of research and experiment!

 

 

 

[GregValiant 1,251]

I do test prints for some things when I have just a bit of material left on a roll.  I figure practice makes perfect.  Right now I don't have any near-empty rolls but Kman did well with it.

 

The only thing I'm absolutely sure of is that computers are not an exact science.

[kmanstudios 1,120]

4 hours ago, GregValiant said:

The only thing I'm absolutely sure of is that computers are not an exact science.

Ain't that the truth...they can only do what they are programed to do and many times, something new will break or at the very least, confuse the system.