STL looks fine, but prints as a solid

Hi all,

I have a blind incert file that I created in the online version. In any kinda of viewer it looks fine; but when I print it, there is no hole in the middle.

How do I fix this?


Load it into Cura and take a look at it in there.

At a guess I would say the faces of the ‘hole’ are reversed so the software can’t see the hole. Look at your model in monochrome and reverse any non white faces.

Thanks guys;

Ive used both Cura and Astroprint and its the same, hole. But when I print…


Half a hole HAHA

Strange right? How do I view it in monochrome?

Thanks everyone!

How about downloading the file to your computer and sharing it here so we can have a look?

Hidden objects?

But anyway; give me a sec and ill get the file

Blind incert.skp (288.7 KB)

Here you go guys! thanks!

Looking at the file from that side, I bet there’s internal faces.

And I was bet right.

Remove the internal faces and it should print correctly. Once you’ve cleaned up the model, you should be able to make it a group or component and see that it shows as solid.

I’m guessing that you tried to draw all of the shape in 2D before starting to make it 3D. If instead, you get the base modeled as 3D and then add the detail for the smaller part on top, you would end up with a solid–no internal faces.


Wow thats awesome! Thanks,

I did draw it as a 2d object then use pull to give it volume. I thought thats how you were meant to do it?

Can I do this with the free version (this is the first thing I have ever made to print lol, I dont really want to pay for something that I might use once a year if that?)

So I made it a group and removed some of the internal faces. But its just made it a hole in the side of it;

You removed the wrong faces. You need to keep the faces lining the hole through the piece.

Probably the easiest thing at this stage would be to start over and model it correctly.

Also make sure you are dragging out the radii of circles on axis and not randomly as you apparently did.

You can do what I showed in the free version.

Ok, let me try again

Ill come back to you

Blind incert (1).skp (201.5 KB)

Ok! Have I done it right this time?


Not quite. Evidently you didn’t quite do what I told you to do. You could edit the model and delete those vertical edges inside the thing. If you’d followed the steps I gave you, you wouldn’t have those edges to delete.

Don’t draw the small part with the notches in it until you’ve made the larger part 3D.

You didn’t drag out the radius of the larger circle on axis.

Although in this particular model that’s not a huge problem, dragging out the radius on axis is a good habit to get into right from the start.

And finally, you have the geometry double wrapped. That is, you have a group inside a group. There’s no need for that.


So what im doing is drawing one circle to a radius of 19mm, editing the notches and putting the hole in the middle to radius of 9mm. then pulling it out to 3mm to create the 3d object.

Once thats done I make the back for it by drawing another circle in the middle and giving it a radius of 20mm. then I pull that out.

You’re saying make both objects flat and mark them all out, then pull them out to make the 3d object?

When I do that; this happens… So what am I doing wrong?

Oh and also; the one I sent before was kinda wrong. I cant have a flat base. It needs to be like the image above… but with the surface thats missing

ah so it’s a little different. I was going to say the second model is not so bad. You left isolated edges inside. You have to have a clean inside. Also there’s no reason to group it twice.

The object you describe so the surface is recessed?

Yes; thats right; recessed.

I thought I could pull one surface up and push the other down; but it doesn’t seem to work that way.

There has to be thickness on the intermediate plane. We don’t know what that dimension is. Note that the space inside that plane is contiguous with the main inside space.

Got ya;

I thought the plane needed some thickness, but I tried to lift it up after I lifted up the other plane. This time I did it the otherBlind incert (3).skp (233.1 KB) way and it seems to have worked.

What do you think?