Unable to 3d print, it seems solid

Hi to everyone.
Ive just created my first part in sketchup a few days ago. (attached)
When i group it it seems to be a solid part but when i want to print it it gives me an error and seems hollow.

Could you please help me to solve this problem and correct my error ?

your model is inside-out.
The grey faces should point inward. White faces outward. this is especially important for 3d printing as the printer needs to know on what side of the face it should be printing material. You can rightclick on a face and click reverse face. then rightclick on the white face and click orient faces.


It seems that the faces of the object are ‘inside-out’.
It will still report as a ‘solid’, but some 3d-printers will object to it…
You should never see ‘back-face color’ - blue-gray in this Style - they should be ‘off-white’ front-faces.

To fix it, edit the Group.
Select an correctly oriented face > context-menu > Reverse Face.
Then with that [now-correctly-oriented] face still selected > context-menu > Orient Faces.
All faces should now be oriented ‘outwards’.
It’ll still be a solid, and should now print in all 3d-apps…

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gear-2.2.skp (1.5 MB)

Try this one. I copied the gear into a new file. SU wanted to fix problems upon opening, not sure what that’s all about.
Also, the new file doesn’t use the 3d printer template (useless) and the file size went from 1.5 mb to 87 KB.

Gear 2.2.skp (87.3 KB)

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I’m confused, two people explain clearly how to correct your model, you then post your model with no comment.
We open it and find you haven’t done what was explained twice.
What is the point of explaining how to do something if you just ignore the advice.

Here you go in moving pictures, this exports as a solid .stl and opens perfectly in my printer software.


Hi thanks for all your replays. The model was uploaded on the same time as my post but took some admin to acept it.
This is my actual model where im working on now.
gear-2.2-final.skp (1.5 MB)

I will try to print the one that shep did for me my own file is still not working.

Thanks i will try to print it tonight.

This one should print but there’s unneeded nesting. I’d explode the top two levels.

Is this gear supposed to be functional or just decorative?

This should just be my first try the actual gear i need does have some more complex geometry around the tooth.

The tooth profile is what I was wondering about.

can you recommend a good tutorial for making gears ?

Modeling gears in Sketchup is really just combining some very fundamental modeling tools and operations. Radial Array is probably the trickiest thing if there’s anything tricky about modeling them. Working with the gear centered on the origin is a good idea and it looks like you did that.

Whenever I’ve wanted to draw gears and such I’ve just done a search for ‘gear dimensions’. You’ll find various sites that give specs regarding tooth shape based on the class of gear. Generally for small gears, especially for 3D printing, I will work at a larger size. If in metric, I’ll use meters instead of millimeters. If inches, I’ll either use decimal units and move mental move the decimal or work in meters as if they are inches. For 3D printing you’ll export an STL file which is unitless and you just need to import it into the slicer with the right units. You can model in meters but import into the slicer in inches if you want.

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I did my gear now with the Involute Gear plugin. It was as easy as it can get.
See the result attached.

spur-gear-30z-v1.2.skp (1.4 MB)

Thanks for everyone helping me out. Awesome community :+1:

Nice gear, but again inside-out…