Re: [OpenSCAD] Exporting multiple colors
OpenSCAD is closely (but not exclusively) coupled to the needs of the 3D
printing user. As such, color in the model is irrelevant. The most common
3D output format, STL, doesn't have a standard representation for color at
all.
The issue of color in 3D printing comes down to what color filament
(assuming an FDM printer) is loaded. So the same model could be printed in
any color of filament.
The issues is more complicated when printing with multiple extruders that
would then allow for multiple colors. The bottom line here is that you
essentially create two models that are printed concurrently. The colors for
the models are determined by the colors of filament loaded in the extruders.
I have a longish article with a lot more info about dual extruder printing
http://www.printrbottalk.com/forum/viewtopic.php?f=21&t=4472 at
Printrbottalk.com that shows specific examples of how all this works.
Bottom line is that even if OpenSCAD did include color info, it wouldn't
help or matter with multi-color printing.
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On Wed, 10 Dec 2014 16:14:33 -0700 (MST)
tdeagan tim@deagan.net wrote:
OpenSCAD is closely (but not exclusively) coupled to the needs of the 3D
printing user. As such, color in the model is irrelevant.
Sorry but this is no longer really true.
How you would extend it into CSG model is another question, most real
world printers texture the outside and texture mapping hardly fits the
CSG model. That's a problem because while you can flip an OpenSCAD model
into say Blender and texture it you can't then easily recompile the model
as you have to reapply all the texture work.
And yes this is relevant to home not just fancy printers, because while
they generally can't print onto the surface for many applications you can
take the texture set, flatten it and vinyl cut or decal print all the
needed sections and then add them to the object.
Alan
Alan Cox wrote
On Wed, 10 Dec 2014 16:14:33 -0700 (MST)
tdeagan <
tim@
> wrote:
OpenSCAD is closely (but not exclusively) coupled to the needs of the 3D
printing user. As such, color in the model is irrelevant.
Sorry but this is no longer really true.
I'm very interested in, but afraid I do not follow, your point. Are you
saying that it is no longer true that OpenSCAD is closely coupled to 3D
printing? Or are you saying that the irrelevancy of color in the model to
3D printing is no longer true?
Since the STL format doesn't natively support color and multicolor printing
is based on independently colorless models (much like all the images in a
color separation for printing are actually grayscale,) I am going to guess
that your point is about the relationship of OpenSCAD to 3D printing.
I absolutely agree that OpenSCAD has become useful for a wide range of 3D
modelling tasks. But its genesis and the vast majority of its use is in the
3D printing worl, so it clearly has a special relationship to 3D printing.
As the engine for the Thingivese Customizer, it's become central to an
important part of the 3D printing world.
How you would extend it into CSG model is another question, most real
world printers texture the outside and texture mapping hardly fits the
CSG model. That's a problem because while you can flip an OpenSCAD model
into say Blender and texture it you can't then easily recompile the model
as you have to reapply all the texture work.
And yes this is relevant to home not just fancy printers, because while
they generally can't print onto the surface for many applications you can
take the texture set, flatten it and vinyl cut or decal print all the
needed sections and then add them to the object.
I apologize, I was less able to follow your thread in this part of your
response. Are you referring to texture mapping in the way that Blender can
apply a flat image to the shell of a model? This is not a common feature
in commercial or personal 3D printers at this time. Even Shapeways only
offers this with one material, Sandstone (no plastics or metals,) and they
require an independent texture map to be sent with the 3D model.
I have a vinyl cutter and have applied appliques to printed models as you
suggest. But the modelling for the vinyl cutter is 2D and requires a
different set of disciplines to make it fit a 3D shape than is used for 3D
modelling alone. I've spent many hours doing the unfolding tasks with Sheet
Metal CAD programs after the 3D model is done so that the 2D model is
usable. 'Unfolding' is usually a different module in 3D modelling programs
than the main modelling section.
As noted, I apologize if I have misunderstood your point.
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Sorry but this is no longer really true.
I'm very interested in, but afraid I do not follow, your point. Are you
saying that it is no longer true that OpenSCAD is closely coupled to 3D
printing? Or are you saying that the irrelevancy of color in the model to
3D printing is no longer true?
The irrelevancy of the colour model hasn't been true for a couple of
years at least. Not just for Shapeways sandstone stuff - there are also 3D
printers using paper layer that do full colour.
Since the STL format doesn't natively support color and multicolor printing
is based on independently colorless models (much like all the images in a
color separation for printing are actually grayscale,) I am going to guess
that your point is about the relationship of OpenSCAD to 3D printing.
STL is just an export format, it's a detail. You can change the format,
extend to one of the STL + colour formats etc.
I apologize, I was less able to follow your thread in this part of your
response. Are you referring to texture mapping in the way that Blender can
apply a flat image to the shell of a model? This is not a common feature
More importantly it can unwrap a 3D object into a set of flat foldable
shapes which can be textured and rewrapped.
in commercial or personal 3D printers at this time. Even Shapeways only
offers this with one material, Sandstone (no plastics or metals,) and they
require an independent texture map to be sent with the 3D model.
It's a trivial piece of post-processing after you've printed it. 3D
printing is just a tool as part of an integrated production system. You
can home 3D print an object, mill it, cast copies and vinyl it these days.
I have a vinyl cutter and have applied appliques to printed models as you
suggest. But the modelling for the vinyl cutter is 2D and requires a
different set of disciplines to make it fit a 3D shape than is used for 3D
modelling alone. I've spent many hours doing the unfolding tasks with Sheet
Metal CAD programs after the 3D model is done so that the 2D model is
usable. 'Unfolding' is usually a different module in 3D modelling programs
than the main modelling section.
I don't intend to be a slave to the tools. I work with a mix of etched
brass, 3D printed OpenSCAD output and vinyl. I don't expect to spend
hours doing unfolding tasks with a CAD program. The reason the tools
exist is so I don't have to spend hours doing pointless automatable jobs.
Many of my textures are machine composited and drawn from the same
rulesets as the 3D and brass. When you have to do a bit of hand tweaking
however it then becomes a pain because you can't preserve things like the
texture bindings.
Alan
Since the STL format doesn't natively support color and multicolor printing
is based on independently colorless models (much like all the images in a
color separation for printing are actually grayscale,)
Yes, STL does not support any way of giving more than just the triangle
information. But almost the whole (free software) 3D printing tool-chain
supports other formats that are able to handle additional information like
multiple volumes, colors, and so on, the newest being AMF (http://stl2.org).
What's still missing is wide support to actually use those features (e.g.
slicers have some support, OpenSCAD currently none at all), so there is
quite a way to go for full color / multi material support...
ciao,
Torsten.
tp3 wrote
Yes, STL does not support any way of giving more than just the triangle
information. But almost the whole (free software) 3D printing tool-chain
supports other formats that are able to handle additional information like
multiple volumes, colors, and so on, the newest being AMF
(http://stl2.org).
What's still missing is wide support to actually use those features (e.g.
slicers have some support, OpenSCAD currently none at all), so there is
quite a way to go for full color / multi material support...
As linked in my initial response (
http://www.printrbottalk.com/forum/viewtopic.php?f=21&t=4472
http://www.printrbottalk.com/forum/viewtopic.php?f=21&t=4472 ) , I've
spent a lot of time documenting the current process for multi-extruder
(which is the primary means of multi-color) FDM 3D printing. I am 100% in
agreement that the toolchain, most importantly post OpenSCAD or other
modeller, is painfully missing the requisite support for multiple colors.
I also am 100% in agreement with the sentiment:
I don't intend to be a slave to the tools.
but as a guy who makes his living writing software I am sadly aware of the
delta between "I don't like the way this works!" and "I've got a wonderful
new toolchain that works great!" Luckily OpenSCAD has a great active
community and can continue to be at the forefront of new development like
color support. But even if it supported it 100%, there is a lot of
additional work downstream before home users will be able to take advantage
of it.
I don't mean to be dismissive of alternate approaches such as 2D appliques
or high-end 3D printing service shops. The OP asked about how they could
print multi-color and I assumed they were talking about home FDM printing.
The link I posted was an attempt to specifically answer this question with
images and examples. I apologize if I didn't address other approaches
outside that mainline, they may soon become more common and hence deserve
attention.
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spent a lot of time documenting the current process for multi-extruder
(which is the primary means of multi-color) FDM 3D printing. I am 100% in
agreement that the toolchain, most importantly post OpenSCAD or other
modeller, is painfully missing the requisite support for multiple colors.
Entirely agreed - I just wanted to expand beyond FDM, because in a lot of
markets (eg model making) we've been using 3D print + vinyls/decals for
some years.
I also am 100% in agreement with the sentiment:
I don't intend to be a slave to the tools.
but as a guy who makes his living writing software I am sadly aware of the
delta between "I don't like the way this works!" and "I've got a wonderful
new toolchain that works great!" Luckily OpenSCAD has a great active
community and can continue to be at the forefront of new development like
color support. But even if it supported it 100%, there is a lot of
additional work downstream before home users will be able to take advantage
of it.
Absolutely.
images and examples. I apologize if I didn't address other approaches
outside that mainline, they may soon become more common and hence deserve
attention.
Sorry wasn't intended to be a criticism but to expand the discussion more
widely beyond the world of FDM.
Alan
On Dec 11, 2014, at 11:15 AM, tdeagan tim@deagan.net wrote:
I’ve spent a lot of time documenting the current process for multi-extruder
(which is the primary means of multi-color) FDM 3D printing. I am 100% in
agreement that the toolchain, most importantly post OpenSCAD or other
modeller, is painfully missing the requisite support for multiple colors.
ok, this is exciting :)
I’m also talking to the developers of the 5-color FFF printer from http://www.ordsolutions.com (we're in the same city). I’m sure you can imagine what sort of challenges they have in terms of slicing and firmware.
If we limit our discussion to FFF-style printer for now, the workflow is essentially to design one (or more) non-intersecting solid volumes per material.
Right now, OpenSCAD doesn’t offer a good way of managing this non-intersecting requirement, but we could fix that. I.e. make it easier to create non-intersecting volumes where each volume is tagged with material info.
Once that is solved, having a convenient “one-click” export into a file (or set of files) which slicers could read directly would make sense.
I tried to create a multi-material test design, but it turned out to be a bit painful: https://www.thingiverse.com/thing:178713
I started scribbling some stuff down here: https://github.com/openscad/openscad/wiki/Multi-material-support
If you have any insight, stuff to add, or want to discuss this, I’d love to touch base.
#openscad on freenode is a good place for more real-time communication.
Cheers,
-Marius
IMHO, the most appealing path for basic/home FFF users would be an AMF export
capability. Even if the AMF format support was initially only STL under the
covers (leveraging AMF's backward compatibility for STL triangles,) and only
added multi-materials.
Slic3r will work with AMF, in fact it's the only way it will do
multi-material. It will convert multiple STLs into an AMF, but there are
some interesting considerations in the way it does so. The order in which
the STLs are added to the AMF determines the association of the model to
extruder. There isn't any way (at this time/version) to re-assign which
extruder goes with which material/model.
From the Slic3r manual
http://manual.slic3r.org/expert-mode/multiple-extruders :
"If a multi-material AMF file already exists, because the CAD program can
export such a format, then this can be loaded into Slic3r in the usual way.
The mapping between object materials and extruders is sequential, i.e. the
first material is assigned to the first extruder, etc."
This implies an awareness in the modelling software (or the user of such,)
which extruder is going to be associated with which material/section/model.
This can be tricky. My printer has a front and back arrangement with the
front 1.75mm bowden extruder and a rear 3mm direct extruder. I have to do a
surprising amount of planning with multi-material prints to get the results
I desire. Other printers have different configurations, leading to
different considerations.
So a story/requirement for the modelling software would be to allow the user
to define which model/material/section is 'first', 'second', etc. (which
could potentially limit the usability of that model by different FFF users,
since the order may need to be different for different printers.)
Fun, tricky stuff!
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