Empathy List Archives

K

kevfquinn

Tue, May 21, 2019 5:24 PM

Ah; so what's probably happening is it has the five non-zero-area faces that
it's happy with, and is just warning that it computed a sixth zero-area face
on the top, which it discarded.

Which all sounds eminently sensible - in general it wouldn't be able to tell
the difference between an intentionally zero-area face and an accidentally
zero-area face, and coding in special exemptions to the warning would be the
wrong thing to do.

In which case the 0.0 scale is fine for the end of an extrusion, no need to
approximate in the source code to avoid the warning.

RayBellis wrote

On 21/05/2019 17:32, A. Craig West wrote:

It is by far the simplest way to generate wedges and cubes, though,
and there is no actual 1D or 2D object, they are just a vertex or edge
of the final 3D object, which are both valid.

They might look like just a vertex or edge, but unless OpenSCAD has
smarts I don't know about, aren't they actually four vertices (or two
edges) occupying the same location(s).

Specifying e.g. 0.001 as the scale factor should produce something
that's physically identical, but without the degeneration to 2D or 1D.

Ray

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Ah; so what's probably happening is it has the five non-zero-area faces that it's happy with, and is just warning that it computed a sixth zero-area face on the top, which it discarded. Which all sounds eminently sensible - in general it wouldn't be able to tell the difference between an intentionally zero-area face and an accidentally zero-area face, and coding in special exemptions to the warning would be the wrong thing to do. In which case the 0.0 scale is fine for the end of an extrusion, no need to approximate in the source code to avoid the warning. RayBellis wrote > On 21/05/2019 17:32, A. Craig West wrote: > >> It is by far the simplest way to generate wedges and cubes, though, >> and there is no actual 1D or 2D object, they are just a vertex or edge >> of the final 3D object, which are both valid. > > They might _look_ like just a vertex or edge, but unless OpenSCAD has > smarts I don't know about, aren't they actually four vertices (or two > edges) occupying the same location(s). > > Specifying e.g. 0.001 as the scale factor should produce something > that's physically identical, but without the degeneration to 2D or 1D. > > Ray > > _______________________________________________ > OpenSCAD mailing list > Discuss@.openscad > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org -- Sent from: http://forum.openscad.org/

A

adrianv

Tue, May 21, 2019 10:42 PM

When I do this in 2019.05 under Linux I get no geometry as a result, so it
is removing the geometry.

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When I do this in 2019.05 under Linux I get no geometry as a result, so it *is* removing the geometry. -- Sent from: http://forum.openscad.org/

M

MichaelAtOz

Tue, May 21, 2019 11:27 PM

adrianv wrote

When I do this in 2019.05 under Linux I get no geometry as a result, so it
is removing the geometry.

Could someone reproduce this.
Adrian can you try it on 2015.03.

It works on windows.

I'm thinking linear_extrude is just calling the 2D scale for each slice, and
the final slice is scale 0, so it just warns as it would any other scale
call.
Interestingly there is no flat top.

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adrianv wrote > When I do this in 2019.05 under Linux I get no geometry as a result, so it > *is* removing the geometry. Could someone reproduce this. Adrian can you try it on 2015.03. It works on windows. I'm thinking linear_extrude is just calling the 2D scale for each slice, and the final slice is scale 0, so it just warns as it would any other scale call. Interestingly there is no flat top. ----- Admin - email* me if you need anything, or if I've done something stupid... * click on my MichaelAtOz label, there is a link to email me. Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above. The TPP is no simple “trade agreement.” Fight it! http://www.ourfairdeal.org/ time is running out! -- Sent from: http://forum.openscad.org/

A

adrianv

Tue, May 21, 2019 11:44 PM

MichaelAtOz wrote

adrianv wrote

When I do this in 2019.05 under Linux I get no geometry as a result, so
it
is removing the geometry.

Could someone reproduce this.
Adrian can you try it on 2015.03.

I couldn't find that ancient version to install. I tried it on RC3.1 and
RC2 and both behaved the same way: no geometry.

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MichaelAtOz wrote > adrianv wrote >> When I do this in 2019.05 under Linux I get no geometry as a result, so >> it >> *is* removing the geometry. > > Could someone reproduce this. > Adrian can you try it on 2015.03. I couldn't find that ancient version to install. I tried it on RC3.1 and RC2 and both behaved the same way: no geometry. -- Sent from: http://forum.openscad.org/

M

MichaelAtOz

Tue, May 21, 2019 11:59 PM

adrianv wrote

that ancient version

Surely you mean vintage, it is the next most recent release...may be
retro...

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click on my MichaelAtOz label, there is a link to email me.

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adrianv wrote > that ancient version Surely you mean vintage, it is the next most recent release...may be retro... ----- Admin - email* me if you need anything, or if I've done something stupid... * click on my MichaelAtOz label, there is a link to email me. Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above. The TPP is no simple “trade agreement.” Fight it! http://www.ourfairdeal.org/ time is running out! -- Sent from: http://forum.openscad.org/

discuss@lists.openscad.org

WARNING: Scaling a 2D object with 0 - removing object

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