What other software uses CSG

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

What other software uses CSG

L Boyd
CSG has the promise to bypass STL for generating printer G code.
What programs actually do this?
Larry
Reply | Threaded
Open this post in threaded view
|

Re: What other software uses CSG

Chow Loong Jin
On Tue, Jul 14, 2015 at 05:42:32AM -0700, L Boyd wrote:
> CSG has the promise to bypass STL for generating printer G code.
> What programs actually do this?

Huh, what? CSG as I know it is Constructional Solid Geometry, which is a
technique of creating 3D models by combining solids, implemented by libcgal and
libopencsg for openscad. Do you mean something else?

Also, generating G-code is a non-trivial thing. I don't really think
it should be part of a CAD program.

--
Kind regards,
Loong Jin

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

signature.asc (836 bytes) Download Attachment
tp3
Reply | Threaded
Open this post in threaded view
|

Re: What other software uses CSG

tp3
In reply to this post by L Boyd
Von: "L Boyd" <[hidden email]>
> CSG has the promise to bypass STL for generating printer G code.
> What programs actually do this?
>
The only one I know of, is IceSL (http://www.loria.fr/~slefebvr/icesl/).

For some discussion about IceSL, see the other thread:
http://forum.openscad.org/color-in-renderer-for-visualization-td12952.html

I think the bigger challenges with G-code generation (for 3d printers)
are things like support structures, bridge handling and similar stuff.
It might be nice to skip STL but on my totally personal wishlist for
slicer improvements, that would be very much at the bottom (just below
support for G2/G3 ;-)

ciao,
  Torsten.

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

Re: What other software uses CSG

bobc
In reply to this post by L Boyd
RepRap Host Software, according to this blog post from 2011 http://blog.reprap.org/2011/10/say-goodbye-to-unsightly-stl-triangle.html. I assume it still does.

There's a suggestion there that Marius added Export to CSG to make this easier. It seems that printing from a CSG model was the "way of the future" back then, but doesn't seem to have caught on.

It is strange how knowledge like this seems to get lost to the community, and has to be "rediscovered".
tp3
Reply | Threaded
Open this post in threaded view
|

Re: What other software uses CSG

tp3
On 07/14/2015 09:07 PM, bobc wrote:
> RepRap Host Software, according to this blog post from 2011
> http://blog.reprap.org/2011/10/say-goodbye-to-unsightly-stl-triangle.html. I
> assume it still does.
>
Maybe, but I'd say this software is dead. It's not updated for 3 years
and https://reprappro.com/software/ does not even mention it.

> There's a suggestion there that Marius added Export to CSG to make this
> easier. It seems that printing from a CSG model was the "way of the future"
> back then, but doesn't seem to have caught on.
>
I guess it hasn't because it's only easy at the first glance and the
benefit is quite limited for a big selection of models.

The article also says...

> > At the moment the supported OpenSCAD primitives are cubes, cylinders
 > > (including frustums and cones), and spheres. I will add extruded polygons,
 > > extruded imported DXFs, polyhedra, and imported STL files later (in that
 > > order, which is also the order of difficulty of doing them...).

...and looking at the change history, that adding of more things never
happened. So the supported feature set is going to work for probably
3% of my own models.

There would be a number of nice benefits of using some higher level
interface between modeler and slicer (or more advanced file formats).
The most interesting one surely the possibility to retain the ideal
information for longer (e.g. leaving a circle a circle instead of
converting to a polygon early).
Getting this to work is not going to be easy, but it might happen
eventually. We'll see what the future brings :-).

ciao,
   Torsten.


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

Re: What other software uses CSG

Neon22
Theoretically a raytracer like POVRay - which does evaluate CSG objects natively - could be used to help create G-Code but its an open problem and the slicing approach seems to be much more prevalent at this stage. There is little advantage to traversing the CSG tree directly to generate slice based g-code. You might as well tessellate to STL and then us the same slicer as everyone else. (IMHO)
Reply | Threaded
Open this post in threaded view
|

Re: What other software uses CSG

L Boyd
In reply to this post by L Boyd
Thanks for the replies. What started me on this path is knowing that most printer firmware has very good circle routines to implement G02 and G03. Going the triangle route loses the knowledge that you wanted a circle.
Larry
Reply | Threaded
Open this post in threaded view
|

Re: What other software uses CSG

Tim Hawkins

Most firmwares on the printers, just convert the arcs to a set of small straight line segments. On Marlin for example it just gets converted to a set of chords of 1mm length.


On Wed, Jul 15, 2015, 21:10 L Boyd <[hidden email]> wrote:
Thanks for the replies. What started me on this path is knowing that most
printer firmware has very good circle routines to implement G02 and G03.
Going the triangle route loses the knowledge that you wanted a circle.



--
View this message in context: http://forum.openscad.org/What-other-software-uses-CSG-tp13144p13167.html
Sent from the OpenSCAD mailing list archive at Nabble.com.

_______________________________________________
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