extrude to center

classic Classic list List threaded Threaded
33 messages Options
12
Reply | Threaded
Open this post in threaded view
|

extrude to center

juerg.maier
got a nice stl from the planet. I isolated the land parts by differing with a sphere. I would like to create a 2 color 3d print from the globe but the landpart is in most places too thin. I have tried to create shells of scaled down instances but either the shells are too far apart or I run into CGAL errors.
Any way to extrude all the vertices towords the center [0,0,0] or any other idea?land7_repaired_1.zip
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

fred_dot_u
If you don't limit yourself to OpenSCAD, you can perform the task you indicate by using MeshMixer.

Import the model into Meshmixer, use Select tool on left side. Press Control-A to select the entire model.
Within the Select tool, select Edit, Offset.
I suggest changing the value in the Distance field rather than using the slider. There are many calculations to be performed and the slider only jumps a small amount (0.03mm in my test) while you can enter any figure for quicker results.

world offset

The above image was done with a 2mm offset. As you can see there are a few artifacts which you may want to remove either before the offset, to improve the processing speed, or after, when they are easier to see!
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

juerg.maier
ehhh, thanks a ton. there looks to be a way for almost everything. just know your tools.
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

cacb
In reply to this post by juerg.maier
On 14. feb. 2017 13:30, juerg.maier wrote:
> got a nice stl from the planet. I isolated the land parts by differing with a
> sphere. I would like to create a 2 color 3d print from the globe but the
> landpart is in most places too thin. I have tried to create shells of scaled
> down instances but either the shells are too far apart or I run into CGAL
> errors.
> Any way to extrude all the vertices towords the center [0,0,0] or any other
> idea? land7_repaired_1.zip
> <http://forum.openscad.org/file/n20432/land7_repaired_1.zip>

I had a look at this model, but it it contains a lot of non-manifold
edges after the sphere subtraction, not generally fixable. There are
also map artifacts in places which I suspect is due to the subtraction.

I think you should go back to the original (is it a scan?) and do the
isolation of land again. If you provide a link to the original I might
have a go at it.

Carsten Arnholm





_______________________________________________
OpenSCAD mailing list
[hidden email]
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

juerg.maier
Even coming back about this! Thank for the help!
My original is rather big and it took Meshmixer with 80% accuracy and a 2
mm offset the best part of a day on my maschine to accomplish it.
You are right, many problems with the resulting .STL. Tried to work on it
with openscad but that crashes even after trying to fix it with netfabb,
netfabb cloud, microsoft 3d tools. And to be able to do things in openscad
I had to divide it into 8 sub-parts (used too much memory otherwise).
I got the original file from here http://www.thingiverse.com/thing:1924651
and tried to use the earth_7_18.stl as my base stl.
I have a dual extruder 3d printer and wanted to print the land in a
different color and hollow out the globe of course.
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

MichaelAtOz
Administrator
a. get a better PC or give up large graphics.
b. Netfabb etc cannot fix everything.
b. Garbage-in, garbage-out, when other utilities say it is garbage, why do you expect OpenSCAD to do better?

So, maybe ask the thingiverse poster to provide a good stl?
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!
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

juerg.maier
sorry Michal, I do not receive your answer as very helpful.
- I only stated that it took a long time on my PC to modify the stl, I did not complain about it
- all the programs I used to clean up the file stated everything is fine with  my STL. Why are you talking of garbage?
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

cacb
In reply to this post by juerg.maier
Thanks for the reference. I will take a look and report back if I find
something that might help.

Carsten Arnholm


On 19. feb. 2017 12:36, juerg.maier wrote:

> Even coming back about this! Thank for the help!
> My original is rather big and it took Meshmixer with 80% accuracy and a 2
> mm offset the best part of a day on my maschine to accomplish it.
> You are right, many problems with the resulting .STL. Tried to work on it
> with openscad but that crashes even after trying to fix it with netfabb,
> netfabb cloud, microsoft 3d tools. And to be able to do things in openscad
> I had to divide it into 8 sub-parts (used too much memory otherwise).
> I got the original file from here http://www.thingiverse.com/thing:1924651
> and tried to use the earth_7_18.stl as my base stl.
> I have a dual extruder 3d printer and wanted to print the land in a
> different color and hollow out the globe of course.


_______________________________________________
OpenSCAD mailing list
[hidden email]
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

cacb
You can try this link, it will last for a couple of days.
https://www.expirebox.com/download/d844bd5d8ce0099fe0a573ab42d174bf.html

It contains 3 files

1) earth_730_all.stl = original STL file (earth_7_30.stl) repaired in my
software + scaled up factor 100

2) earth_730_sphere.stl - a "near sphere" used for subtraction
radius = 99.47
translated (0.437,-0.21,-0.312)

3) earth_730_diff.stl = difference between 1 & 2 computed outside
OpenSCAD. It is somewhat crude, e.g. in south-east asia, but I don't
think it is possible to improve very much.


With OpenSCAD, the following would be an equivalent operation:

difference() {
   import("earth_730_all.stl");
   translate([0.437,-0.21,-0.312])sphere(99.47);
}

However, I could not get this to work in OpenSCAD version 2016.10.04
(git 7e0935d) Windows

Carsten Arnholm

On 19. feb. 2017 20:00, Carsten Arnholm wrote:

> Thanks for the reference. I will take a look and report back if I find
> something that might help.
>
> Carsten Arnholm
>
>
> On 19. feb. 2017 12:36, juerg.maier wrote:
>> Even coming back about this! Thank for the help!
>> My original is rather big and it took Meshmixer with 80% accuracy and a 2
>> mm offset the best part of a day on my maschine to accomplish it.
>> You are right, many problems with the resulting .STL. Tried to work on it
>> with openscad but that crashes even after trying to fix it with netfabb,
>> netfabb cloud, microsoft 3d tools. And to be able to do things in
>> openscad
>> I had to divide it into 8 sub-parts (used too much memory otherwise).
>> I got the original file from here
>> http://www.thingiverse.com/thing:1924651
>> and tried to use the earth_7_18.stl as my base stl.
>> I have a dual extruder 3d printer and wanted to print the land in a
>> different color and hollow out the globe of course.
>
>
> _______________________________________________
> OpenSCAD mailing list
> [hidden email]
> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
>


_______________________________________________
OpenSCAD mailing list
[hidden email]
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

MichaelAtOz
Administrator
cacb wrote
1) earth_730_all.stl = original STL file (earth_7_30.stl) repaired in my
software + scaled up factor 100

...

However, I could not get this to work in OpenSCAD version 2016.10.04
(git 7e0935d) Windows
"repaired"??
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!
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

MichaelAtOz
Administrator
In reply to this post by cacb
Carsten, interestring pattern your code generates, not in the thingiverse stl;

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!
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

MichaelAtOz
Administrator
MichaelAtOz wrote
 not in the thingiverse stl;
...well there is a different pattern;
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!
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

juerg.maier
thanks for all the help. Will be out today but will have a look at the files soon.

@Michael. Could not follow your statements. Your first picture shows some funny stuctures on the see part? And how did you get the second better looking result? Just fixing the stl with netfabb studio  basic?
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

cacb
In reply to this post by MichaelAtOz
On 2017-02-20 01:35, MichaelAtOz wrote:
> "repaired"??

Thanks for your input. It worked, yes.

Carsten Arnholm

_______________________________________________
OpenSCAD mailing list
[hidden email]
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

cacb
In reply to this post by MichaelAtOz
On 2017-02-20 01:43, MichaelAtOz wrote:
> Carsten, interestring pattern your code generates, not in the
> thingiverse
> stl;
> <http://forum.openscad.org/file/n20499/earth_fixed_pattern.jpg>

The pattern originates from the thingiverse STL as you observed. The
repair process may have modified it slightly, but does not initiate such
patterns. The sphere that was subtracted has a different pattern.

Carsten Arnholm






_______________________________________________
OpenSCAD mailing list
[hidden email]
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

MichaelAtOz
Administrator
In reply to this post by cacb
cacb wrote
On 2017-02-20 01:35, MichaelAtOz wrote:
> "repaired"??

Thanks for your input. It worked, yes.
Well, maybe worked, but by what definition.

The image above (with meshlab in the window title), is the "repaired" stl.
In Meshlab, showing 42 non-manifold edges, with 166 faces on them, then all the coloured bit are the preview of self-intersections.
A stl with self-intersections & non-manifold edges as not "repaired".

The second one, "interestring pattern your code generates" is a view in Netfabb, note the small yellow bits, those are holes, not good. (there are no holes in the thingiverse original)
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!
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

cacb
On 2017-02-20 11:24, MichaelAtOz wrote:
> cacb wrote
>> On 2017-02-20 01:35, MichaelAtOz wrote:
>>> "repaired"??
>>
>> Thanks for your input. It worked, yes.
>
> Well, maybe worked, but by what definition.


By the definition that I was able to make a difference, giving a
reasonable result. I tried various ways to do the same in OpenSCAD but
without any success. Perhaps you can demonstrate how to do it, I am
truly interested in any better way to do such things.

Carsten Arnholm




_______________________________________________
OpenSCAD mailing list
[hidden email]
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

juerg.maier
After giving many unsuccessful tries I am asking now from the originator
whether the data source used to create the complete globe could also be
used to generate a land-globe only.
I think because some land parts can be below sea level and some very
slightly above a good representation can not be accomplished by simply
subtracting a sea-sphere from the complete globe.
And I would still need a thickness addition for the land parts to make them
printable with a FDM printer.
Carsten has shown me that Meshmixer has an Offset-function to thicken the
land parts but the result looks rather rough or not very detailed to me?
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

cacb
In reply to this post by cacb
On 20. feb. 2017 11:46, [hidden email] wrote:

> On 2017-02-20 11:24, MichaelAtOz wrote:
>> cacb wrote
>>> On 2017-02-20 01:35, MichaelAtOz wrote:
>>>> "repaired"??
>>>
>>> Thanks for your input. It worked, yes.
>>
>> Well, maybe worked, but by what definition.
>
>
> By the definition that I was able to make a difference, giving a
> reasonable result. I tried various ways to do the same in OpenSCAD but
> without any success. Perhaps you can demonstrate how to do it, I am
> truly interested in any better way to do such things.

I had another go and found the reason for the hole artifacts that were
observed. The reason was that the original globe model was only 1mm in
radius, so my default coordinate tolerances were unsuitable.

By adjusting the coordinate tolerance to fit and repeating the process,
the result has no holes that I can find and also allowed subtraction of
a more refined sphere. The result is a much more recognizable outline of
e.g. Europe.

Obviously, the true shape of the earth at sea level is not a sphere but
a geoid, so this method is still a rough approximation.

https://www.expirebox.com/download/43215f41975555d30c66784b0f517875.html

Carsten Arnholm

_______________________________________________
OpenSCAD mailing list
[hidden email]
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
Reply | Threaded
Open this post in threaded view
|

Re: extrude to center

cacb
In reply to this post by juerg.maier
On 20. feb. 2017 21:03, juerg.maier wrote:

> After giving many unsuccessful tries I am asking now from the originator
> whether the data source used to create the complete globe could also be
> used to generate a land-globe only.
> I think because some land parts can be below sea level and some very
> slightly above a good representation can not be accomplished by simply
> subtracting a sea-sphere from the complete globe.
> And I would still need a thickness addition for the land parts to make them
> printable with a FDM printer.
> Carsten has shown me that Meshmixer has an Offset-function to thicken the
> land parts but the result looks rather rough or not very detailed to me?

To be fair, it wasn't me who showed you that.

See the other comment with the new version I created.  I guess it is
possible to "extrude" the underside downwards, but it will have to
account for the offset centre.

offset = (0.437,-0.21,-0.312)
radius = 99.479

Carsten Arnholm

_______________________________________________
OpenSCAD mailing list
[hidden email]
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org
12