Alternatively: https://www.reprap.me/extruder/diamond-hotend [image: image.png] that could do your shape too, but I don't know about what software. On Wed, 15 Sept 2021 at 16:24, Doug Moen <doug@moens.org> wrote: > On Tue, Sep 14, 2021, at 9:40 AM, Michael Möller wrote: > > Colour or Support only makes sense for a multi head 3D printer. > > > I think you are talking about consumer grade FDM printers, which do > multi-colour prints by switching between different coloured filaments. But > if you use a service provider like ShapeWays for printing, then there are > multiple technologies for full colour printing, where you have full CMYK > control over the colour at each print position. > > I dunno, maybe this is considered out of scope for OpenSCAD. One of the > reasons I created my own OpenSCAD-like language was to do full colour > printing like this. For output, I use file formats that support vertex > colouring (where you specify a separate colour for each vertex in the > model). 3MF is one of the file formats that supports vertex colouring. > > Here's an example of a print that I created using Curv, exported as > coloured vertexes, and printed using Shapeways: > > > > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >

On Wed, Sep 15, 2021, at 3:06 PM, Michael Möller wrote: > Alternatively: https://www.reprap.me/extruder/diamond-hotend I haven't tried this specific hotend, but I looked at output from another colour-mixing FDM printer at a makerspace and talked to the owner. My impression is that it works great if you want to change colours each layer. But you can't switch colours every 100 microns in the X and Y axes, like you can with the expensive printers at Shapeways and other service providers. That other printer required the use of a purge tower each time the colour changed. So X-Y gradients aren't possible. If you look at models created with colour-mixing FDM, either there are a small number of distinct colours which appear in large blocks (no gradients), just like the models from multi-filament FDM, or there is a gradient along the Z axis.

So I think the summary of this subtopic is that there are real use cases not only for color control over individual pieces of a model, but also for finer-grained control like gradients or volumetric patterns. Simpler cases, which could be modeled as color changes but are really material changes, would be useful for mere-mortal devices like Prusa's $300 five-material upgrade package.  (That kit alone is a reason why I'm considering picking up a Prusa printer.) The only question, in my mind, is how the integration with the slicer works.