3d printing model errors- help!

Hi there. Newbie here. I’m a teacher who is tutoring a student, and one of his subjects is 3d design. We’re trying to print a cup from the 3d warehouse, but it keeps saying model errors: Your model is not manifold. It appears there are some holes, but I’m not sure how to fix them. Can anyone help explain what I should do? STL attached. Thanks for your help!
3dcup3.stl (32.6 KB)


Can you share the .skp file? It would help us identify what is preventing it from being solid.

The .stl exhibits a bunch of reversed faces, holes in the surface and the bottom has no thickness.

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I am fairly sure this file was not designed to be printed… it has a lot of backwards faces and overlapping geometry. Just becuse it is on 3DWarehouse does not mean it was created to be printed.

On that STL there are reversed faces, there are small holes in a bunch of places and the components that make up the cup on the whole are not solid.

You probably need to learn to use SketchUp for solid modelling
SketchUp Campus
, or find a model designed to be printed in the first place - the 3D warehouse isn’t really the place for that.

Thingiverse - Digital Designs for Physical Objects might be better to get a cup from

Here I’ve fixed the incorrect face orientation. All blue backfaces must face the print media and the white ones must face air. I’ve redrew the cup itself so there are no holes and so the bottom has thickness.

I also softened edges so it looks nicer although that isn’t a requirement to be printable.

How big is the cup supposed to be?

Thank you so much for your quick response and help! You are awesome! We were just doing a mini cup, about 3-4 inches. Do you think that will print okay on my printer? I have a Ender Max 3 Neo. I’ve only printed bigger things on my printer.

Thank you again for your help!

Thank you! I will definitely see if I can find a similar cup on Thingyverse and we can check out the SketchUp Campus as well!

Hi there! Yes, when I see my student tomorrow I can ask him to send me the .skp file and I will post. Thanks for your help!

It may not be a big deal at this stage. Do you know how big the cup is supposed to be?

Hi there. Thank you so much for your help. The size is:
7.9 cm from edge of handle to other side, 6 cm side to size horizontally, and vertically 7.5 cm.

Thanks Dave!
3dcup.skp (676.0 KB)

The SKP file is attached.

Take a look at this version of the model and compare it to the original. It has the corrections I indicated previously.

I modeled it as if millimeters are meters to avoid issues with tiny faces. If the attached .stl is imported into the slicer with mm as the units it should be the right size. You can see in slicer here it is 75mm tall.

Cup.skp (63.0 KB)
Cup.stl (27.3 KB)

My student and I really appreciate you helping us! Here’s what he has to say:
Thanks Dave the cat!

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I’m glad it helped.

Curious about where the cat comes from.

A brown “cat” with a bowler hat perhaps?

Maybe. But it’s a prairie dog. :wink:


lol! :joy: