Problem after export - added extra (very thin) surface



Hello i made a model for 3D print but i have a problem while exporting model.
I exported project to .obj file but when i opened newly created .obj file i noticed that model have extra surfaces which i cant see while working in sketchup.
These images illustrate the problem (first is from sketchup, second from 3D viewer).

How can i get rid off extra surfaces?
Thanks in advance :slight_smile:


Is the object you are trying to 3d-print a “manifold-solid”.
“Entity Info” should report it as being a “Solid”.
It should be a ‘container’ - a group or component-instance - that has the following properties…
It only contains geometry - edges and faces [although non-interactive Guides are acceptable, they are also best avoided].
Every edge must support exactly two faces.
That is, there can be no faceless edges, no edges with only one face - flaps or shelves, or perimeters to “holes”, no edges supporting more that two faces - no internal partition faces with three or more faces per edge, or otherwise solid objects sharing a common edge - e.g. two ‘cubes’ touching at a common edge that has four faces.

Also all faces of the ‘solid’ object should be oriented to face outwards - i.e. you should never see the ‘back-faces’.

Another possible but obscure issue is that although an object might report as ‘solid’ it can be unprintable in3d…
That is if the geometry is self-intersecting - so some faces pass through others.
These cannot be printed.
If the geometry inside the ‘container’ is selected and the context-menu used to intersect with itself results in an object that no longer reports as a ‘Solid’ in ‘Entity Info’, then something is wrong, and you probably need to delete internal partition faces etc…


Yes, object is solid. I use Solid Inspector for checking for any problems. I tried to make union on all elements before exporting but the result was the same (final project must be printed as couple of parts and then glued together).
IMO object is very simple and meets requirements from your post, i had some contact with 3D printing before and i know some basics like object filled with water can’t have any leaks etc.
There is one of problematic objects:
element.skp (1.2 MB) (yes i know that its dimensions are huge, but before printing i plan to resize it, i just modeling 1:1 the real object).
What i made wrong and how i could fix it?


I exported it. There seems to be no problem.


Thats weird. I used 3D Viewer build in windows 10 and some online 3D object viewers and in all of these the problem exist. But when i used 3D Builder which is also build in windows 10 (you used the same program) i got correct model.
So, hmm this is a 3D viewer issue or model issue?

It seems to be an issue in Sketchup. When i exported unchanged model from 3D Builder to obj file all other 3D viewers display model correctly.


Looks like something in the other program…

There is an extra line at the base of the stairs that may be worth erasing, but other than that, it is a good solid. Looks fine in Mesh Lab, Cura, and Makerware!


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