Hello,
it's the first time that I will put a question to a forum. So please be
forgiving if i do not fully comply with the netiquette.
My problem is that the prewiew fails (has errors). I know that the problem
is caused by the opengl version and I know the work around with "% and #". I
have an old SONY Vaio laptop with Win 10 with HD 3000 GPU. Natively there is
no W10 driver but I installed (found the possibliity in the internet) the
Intel driver 9.17.10.4459. This driver supports opengl 3.1. But I get on
startup this warning:
http://forum.openscad.org/file/t2875/Waring.jpg
Here OpenGL version is mentioned with 1.1.0 Why is this so? See
VersionInfo.txt http://forum.openscad.org/file/t2875/VersionInfo.txt  for
more. Here The opengl version is 1.1.0, too. But I am nearly sure to have
OpenGL version > 2.0. The CAPS viewer output is :
http://forum.openscad.org/file/t2875/Caps_Viewer.jpg
And I can run the Open GL 3.x - Illuminated Torus demo without a problem.
All other demos 2.x are also running. The open GL extension viewer also says
OpenGL 3.1.
What could I do that OpenSCAD gets the right (?) OpenGL version and the
preview running correct? And where gets OpenSCAD the version info from?
I am happy for your suggestions and I am sorry for ma bad English. If more
information is needed - please write what I could do.

--
Sent from: http://forum.openscad.org/

No solution, but maybe I'm encountering the same problem.

When you start OpenSCAD up, do you get a yellowish preview pane with
axes, or do you get an empty white box?

Maybe 1/3 of the time I end up with an OpenGL warning and an empty white
box.  If I try again a few times it'll usually usually eventually
succeed.  This may be correlated to which of my two monitors (with
different display adapters) the window initially comes up on, but I
haven't found anything that reliably controls whether or not it works. 
Once it's up and working it continues to work on either monitor.

Thanks to JordanBrown and cacb for their pity. Now I know I'm not alone ...I
hoped get so much replies like "Polyhedron generation from two parallel
polygones?" Is there someone of the programmers who could tell me how QT(?)
gets the openGL version?Is there any possibility to override the version
checking? Any suggestion is very welcome. I love OpenSCAD, but it is very
hard to model something in partial blind flight.

--
Sent from: http://forum.openscad.org/

I don't know why it would fail to detect the driver but
according to https://doc.qt.io/qt-5/windows-requirements.html
you could try setting the environment variable:

QT_OPENGL=desktop

or try

QT_OPENGL=software

If that does not change anything, another option could be
adding the Mesa Software driver to the OpenSCAD folder:

https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Building_on_Microsoft_Windows#OpenGL_(Optional)

While switching to software rendering might slow down
things a little bit, it should not have a huge impact as
OpenSCAD does not make much use of GPU side rendering
currently.

ciao,
Torsten.

Thank you Torsten!
Your last hint was the solution. Setting the environment variable QT_OPENGL
made no difference but putting the Mesa OpenGL32.dll into OpenSCAD dir
worked. First I had some problems finding the dll for Win 64. At the end I
found the dll created by Federico Dossena. This works well with the
"goldfeather algorithm" checked. Without this the preview had some errors.
Now everything is displayed perfectly and the speed is very high. I am happy
to get rid of the "%" and "#" before the most of the lines...
Thank you and all the others for the perfect support.

--
Sent from: http://forum.openscad.org/