Export SKP to STL More Lines Issue


I am trying to have 3d print made, however, the STL version of the file contains a few more angles than there are in the initial SKP file. Is there a way to prevent these? Please find files attached.

Question.skp (160.0 KB)
Question.stl (12.2 KB)

Both have the same amount of triangulation, but sketchup uses a visual trick to make it look smooth.
The one on the left is the stl, the middle the .skp and the right the .skp with the softening removed.

Thank you for the response. Are there any easy non-visual trick methods to smoothen this triangulation?

From your posts it sounds to me like you don’t realize that in .stl everything is represented by triangles. There is no other kind of geometry in .stl aside from edges forming triangles. So, no, other than a visual effect in the stl viewing app, there is no way to eliminate those triangles.

On a related note, I assume that the twist between the top and bottom of the model is intentional? SketchUp itself can only create planar faces so, as @Box pointed out, it has split the twisted sides into triangles using hidden edges. The hexagonal bottom is the only part that is planar.

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Sketchup never uses curves, everything is edges and flat faces. Everything is triangulated to create curves. To 3d print a smooth curve you need more segments. You can stitch the edges together or use an extension.
This is a quick version. The offscreen context menu option you can’t see is, Divide.
More curve


Great, thank you! My knowledge is quite limited, and to prove this even more, now I am having trouble fitting the edges of the six sides together. Is this possible?

SIVUT.skp (271.6 KB)

Hello again,

Here is a screenshot of the result. Can anyone think of a way to make the edges fit?

The info I gave you was a start not necessarily the complete how to. I was just suggesting curviloft as a tool that you could look at to solve your issue. 100 segments is a bit of overkill, I would have used 4 or 8 or something like that. The shaoe you have in your model is very flat, so to get the edges to join you need to give it a specific edge to follow, this edge could also be divided to perhaps give more curve. Then use the 4 edges to create the shape.
Curviloft joints

Thank you again. However, now i still seem to have the triangles. Also, now there are problems when I try to thicken the shape with joint push and pull.

What shape do you actually want?

Do you really want the top and bottom hexagons not aligned to each other?

As it is, you have this (top view, parallel projection):

Your ‘vase’ would be much simpler it the hexagons were aligned. Then the sides would be flat single faces, you could copy and scale down the outside to create the inside, connect the top faces, and have a solid for 3D printing.

Ultimately, when exporting to STL, the result will consist of triangles. As Dave shows, the transition can be made smoother by increasing the number of them. But STL is a triangulated format so regardless of the modelling application or method, triangles is the result.

Fredo’s Joint PushPull has several methods to choose. You might try the Thicken method.

Here I have used 48 segments on all four edges to create a detailed slight curve. Note the distortion at the corners from using Joint pushpull. You need to understand that sketchup can only do what you tell it to do and the result will always be flat faces which will be triangulated in stl files.
You can see here all the triangulation that sketchup has effectively ‘hidden’ by smoothing the result. This is what an stl will look like.

What are you actually trying to produce, you keep changing the shape?
The shape you are playing with, while very basic is actually quite complex in sketchup terms. It’s an unnatural shape, straight edges when twisted in real life don’t naturally form curves, they stretch and distort depending on the material.

This is three versions of the same shape, on the right single edges, middle 48 top and bottom single verticals and the left is 48 all edges.
You can see the huge angle on the right, the striations in the middle and the nice smooth shape on the left.

You also get a better result by using the copy/paste scale method rather than Joint Pushpull.

Thank you again for the responses. I managed to do this with scaling and 48 edges all around.

I am trying to produce different sized vessels to be cast with the same twisted design.

And more trouble. If I am scaling the shape down to add thickness, the faces between the scaled and original are not solid - probably due to geometry being more complex again (and it seems I cannot yet again divide and use Curviloft in these.

Also, is there a way I could have overall thickness of 5mm all around with copy in place and scale method?

There are lots of things you can do depending on exactly what the shape is, if it is even on the a/y axis you can scale x,y with the actual size you need by adding the unit, but that probably won’t be accurate on the shape in your latest screenshot. You could give one panel thickness before you array it, so many option and there is no one right option.
Perhaps the simplest for an even thickness on a shape that is difficult to scale to a specific size would be to skin the whole thing.
Build up all the edges you need and use the skin contours button. Once you have to two skins you need to explode them orient the faces correctly and enclose the ends.
Skin contour

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More trouble.

When I upload a STL file for 3d printing I do get uneven bottom of the shape and they cannot print now flat. I have tried with less division of the edges and different conversions. Anyone know why this would be?Screenshot 2021-09-29 at 12.01.02

It would help if you added the model. It depends how you made the bottom face, you can see the distortion in your image, but is it fixable can’t be guessed.