Empathy List Archives

R

rogerfroud

Fri, Jun 26, 2020 7:55 AM

Searching the forum, it would appear that that only way to get a usable 3D
model that can be edited in other 3D modelling packages is to somehow
convert the .stl output.
This is really not an acceptable solution either technically or practically.
What's needed is to be able to output OpenSCAD models in .stp format.

OpenSCAD is such a powerful and clever tool, but its usefulness is only a
fraction of what it could be if the models it creates could be used in other
assemblies or modified. I have a simple bevel gear arrangement that requires
a portion of the gear to be removed. This is the sort of thing that ought to
be easy.

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

Searching the forum, it would appear that that only way to get a usable 3D model that can be edited in other 3D modelling packages is to somehow convert the .stl output. This is really not an acceptable solution either technically or practically. What's needed is to be able to output OpenSCAD models in .stp format. OpenSCAD is such a powerful and clever tool, but its usefulness is only a fraction of what it could be if the models it creates could be used in other assemblies or modified. I have a simple bevel gear arrangement that requires a portion of the gear to be removed. This is the sort of thing that ought to be easy. -- Sent from: http://forum.openscad.org/

P

Parkinbot

Fri, Jun 26, 2020 10:43 AM

This question has a really long beard. Use a forum search to find answers for
the whys and the why nots.

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

This question has a really long beard. Use a forum search to find answers for the whys and the why nots. -- Sent from: http://forum.openscad.org/

TP

Torsten Paul

Fri, Jun 26, 2020 11:02 AM

On 26.06.20 09:55, rogerfroud wrote:

What's needed is to be able to output OpenSCAD models
in .stp format.

Do you have a suggestion how to make this happen? What's
the reason for the urgency?

ciao,
Torsten.

On 26.06.20 09:55, rogerfroud wrote: > What's needed is to be able to output OpenSCAD models > in .stp format. Do you have a suggestion how to make this happen? What's the reason for the urgency? ciao, Torsten.

A

amundsen

Fri, Jun 26, 2020 3:09 PM

What is so bad with the .stl format?

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

What is so bad with the .stl format? -- Sent from: http://forum.openscad.org/

A

AKADAP

Fri, Jun 26, 2020 5:23 PM

FreeCAD can import OpenSCAD designs and output a huge number of formats, but
I don't think you will be satisfied with the results.
OpenSCAD converts all curved surfaces into an array of triangles which makes
them look ugly in other formats, and I am sure will make editing them a
pain.

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

FreeCAD can import OpenSCAD designs and output a huge number of formats, but I don't think you will be satisfied with the results. OpenSCAD converts all curved surfaces into an array of triangles which makes them look ugly in other formats, and I am sure will make editing them a pain. -- Sent from: http://forum.openscad.org/

NH

nop head

Fri, Jun 26, 2020 6:35 PM

Yes OpenSCAD internally represents geometry as a set of polygonal faces
with vertices expressed as doubles, so it isn't much different to STL,
which expresses them as triangles with float coordinates.

I think the FreeCad converter does convert some cylinders into true
cylinders but then it doesn't match the OpenSCAD design as they are really
polygonal prisms in OpenSCAD.

On Fri, 26 Jun 2020 at 18:24, AKADAP Douglas_Peale@comcast.net wrote:

FreeCAD can import OpenSCAD designs and output a huge number of formats,
but
I don't think you will be satisfied with the results.
OpenSCAD converts all curved surfaces into an array of triangles which
makes
them look ugly in other formats, and I am sure will make editing them a
pain.

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

OpenSCAD mailing list
Discuss@lists.openscad.org
http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org

Yes OpenSCAD internally represents geometry as a set of polygonal faces with vertices expressed as doubles, so it isn't much different to STL, which expresses them as triangles with float coordinates. I think the FreeCad converter does convert some cylinders into true cylinders but then it doesn't match the OpenSCAD design as they are really polygonal prisms in OpenSCAD. On Fri, 26 Jun 2020 at 18:24, AKADAP <Douglas_Peale@comcast.net> wrote: > FreeCAD can import OpenSCAD designs and output a huge number of formats, > but > I don't think you will be satisfied with the results. > OpenSCAD converts all curved surfaces into an array of triangles which > makes > them look ugly in other formats, and I am sure will make editing them a > pain. > > > > -- > Sent from: http://forum.openscad.org/ > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >

TP

Torsten Paul

Fri, Jun 26, 2020 6:47 PM

On 26.06.20 20:35, nop head wrote:

I think the FreeCad converter does convert some cylinders
into true cylinders but then it doesn't match the OpenSCAD
design as they are really polygonal prisms in OpenSCAD.

That is certainly true for the mesh rendering stage which
is the normal mode of operation. However the CSG representation
(export as CSG) does retain the information as long as only
the basic CSG operations are used while resolving modules and
functions.
I assume that is what FreeCAD is using and this would allow
exporting to more useful STEP with a couple of limitations
(e.g. minkowski() would still resolve to a mesh).

ciao,
Torsten.

On 26.06.20 20:35, nop head wrote: > I think the FreeCad converter does convert some cylinders > into true cylinders but then it doesn't match the OpenSCAD > design as they are really polygonal prisms in OpenSCAD. That is certainly true for the mesh rendering stage which is the normal mode of operation. However the CSG representation (export as CSG) does retain the information as long as only the basic CSG operations are used while resolving modules and functions. I assume that is what FreeCAD is using and this would allow exporting to more useful STEP with a couple of limitations (e.g. minkowski() would still resolve to a mesh). ciao, Torsten.

B

berkenb

Fri, Jun 26, 2020 6:53 PM

tp3 wrote

I assume that is what FreeCAD is using and this would allow
exporting to more useful STEP with a couple of limitations
(e.g. minkowski() would still resolve to a mesh).

This is correct, I have successfully used this in the past a few times. It
is important to not explicitly set $fn/$fa/$fs modifiers before exporting
to CSG, that way FreeCAD attempts to represent primitives in their
'abstract' form. FreeCAD also seems to struggle with 2D operations exported
from OpenSCAD.
So it's not a complete solution, but can be quite useful in many cases.

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

tp3 wrote > I assume that is what FreeCAD is using and this would allow > exporting to more useful STEP with a couple of limitations > (e.g. minkowski() would still resolve to a mesh). This is correct, I have successfully used this in the past a few times. It is important to *not* explicitly set $fn/$fa/$fs modifiers before exporting to CSG, that way FreeCAD attempts to represent primitives in their 'abstract' form. FreeCAD also seems to struggle with 2D operations exported from OpenSCAD. So it's not a complete solution, but can be quite useful in many cases. -- Sent from: http://forum.openscad.org/

discuss@lists.openscad.org

.stp output urgently required