I'm not sure what I'm experiencing here, and I'd like some guidance. I have
a somewhat older laptop running Win 10 Home, with an Intel on-board video
card; and, a desktop running Win 11 Pro and a newly upgraded RTX 5060 Ti
(it previously had a GTX 710, I think? I can check if it's important).

After upgrading, the following simplified OpenSCAD code doesn't have the
same behavior:

// pretty much BOSL2's implementation of tube():
outside = [ [0, 5], [10, 5], [10, 0], [0, 0] ];
inside = [ [0, 5.1], [5, 5.1], [5, -0.1], [0, -0.1] ];
difference(){
rotate_extrude(angle=360) polygon(outside);
rotate_extrude(angle=360) polygon(inside);
}

Pre-upgrade, and on the laptop, this previews and renders pretty much as
you'd expect. It produces the tube-shape about the same for both the
2021.01 GA release, and a recent 2025-07-esque nightly build. No problems
there.

Post-upgrade, the preview looks as though there's a convexity issue: on the
2021.01 GA, the preview has a broken internal donut tube appearance (image
A, attached); on a recent 2025.07 nightly, no preview is shown at all
(image B). Fully rendering and STL exporting under both versions seems to
be fine (ie, it produces a solid shape that can be sliced with no errors,
etc) (images C, D, attached).

Adding convexity=1 to both rotate_extrude() calls seems to clear up
previews on the upgraded box; they have no effect on the laptop (expected).
I'm guessing that this something to do with the desktop's version of
OpenGL, but I am not an expert. I've attached the output of the library and
build info for 2021.01 and 2025.07 for both hosts (four in total).

Adding those calls through this collection of models and the libraries they
depend on isn't really tenable. Downgrading the desktop to the previous
video card is possible to get unblocked, but if that's what's happening I'd
suspect other people would have this same problem too, and I haven't seen
"don't use this card" or "don't use this version of OpenGL" guidance here;
I'd like to avoid downgrading.

Can anyone speak to what's happening, why this behavior is different? Is
this expected?

--

• Jon Gilbert
  jong@jong.org / jgilbertsjc@gmail.com

What happens when you enable Goldfeather in preferences?

-Revar

On Aug 6, 2025, at 6:22 PM, Jonathan Gilbert via Discuss <discuss@lists.openscad.org> wrote:

I'm not sure what I'm experiencing here, and I'd like some guidance. I have a somewhat older laptop running Win 10 Home, with an Intel on-board video card; and, a desktop running Win 11 Pro and a newly upgraded RTX 5060 Ti (it previously had a GTX 710, I think? I can check if it's important).

After upgrading, the following simplified OpenSCAD code doesn't have the same behavior:

// pretty much BOSL2's implementation of tube():
outside = [ [0, 5], [10, 5], [10, 0], [0, 0] ];
inside = [ [0, 5.1], [5, 5.1], [5, -0.1], [0, -0.1] ];
difference(){
rotate_extrude(angle=360) polygon(outside);
rotate_extrude(angle=360) polygon(inside);
}

Pre-upgrade, and on the laptop, this previews and renders pretty much as you'd expect. It produces the tube-shape about the same for both the 2021.01 GA release, and a recent 2025-07-esque nightly build. No problems there.

Post-upgrade, the preview looks as though there's a convexity issue: on the 2021.01 GA, the preview has a broken internal donut tube appearance (image A, attached); on a recent 2025.07 nightly, no preview is shown at all (image B). Fully rendering and STL exporting under both versions seems to be fine (ie, it produces a solid shape that can be sliced with no errors, etc) (images C, D, attached).

Adding convexity=1 to both rotate_extrude() calls seems to clear up previews on the upgraded box; they have no effect on the laptop (expected). I'm guessing that this something to do with the desktop's version of OpenGL, but I am not an expert. I've attached the output of the library and build info for 2021.01 and 2025.07 for both hosts (four in total).

Adding those calls through this collection of models and the libraries they depend on isn't really tenable. Downgrading the desktop to the previous video card is possible to get unblocked, but if that's what's happening I'd suspect other people would have this same problem too, and I haven't seen "don't use this card" or "don't use this version of OpenGL" guidance here; I'd like to avoid downgrading.

Can anyone speak to what's happening, why this behavior is different? Is this expected?

--

• Jon Gilbert
  jong@jong.org / jgilbertsjc@gmail.com

<consolidated laptop n desktop info.txt>

<A rotate_extrude difference preview 2021.01.png>

<B rotate_extrude difference preview 2025.07.11.png>

<C rotate_extrude difference render 2021.01.png>

<D rotate_extrude difference render 2025.07.11.png>

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