Two test towers, showing the palette potential of three (R, B, Y) filaments.

FullSpectrum Is Like HueForge For 3D Models, But Bring Your Toolchanger

March 17, 2026 by Tyler August 18 Comments

Full-color 3D printing is something of a holy grail, if nothing else, just because of how much it impresses the normies. We’ve seen a lot of multi-material units in the past few years, and with Snapmaker’s U1 and the Prusa XL, it looks like tool changers are coming back into vogue. Just in time, [Ratdoux] has a fork of OrcaSlicer called FullSpectrum that brings HueForge-like color mixing to tool-changing printers.

The hook behind FullSpectrum is very simple: stacking thin layers of colors, preferably with semi-translucent filament, allows for a surprising degree of mixing. The towers in the image above have only three colors: red, blue, and yellow. It’s not literally full-spectrum, but you can generate surprisingly large palettes this way. You aren’t limited to single-layer mixes, either: A-A-B repeats, and even arbitrary patterns of four colors are possible, assuming you have a four-head tool-changing printer like the Snapmaker U1 this is being developed for.

FullSpectrum is, in fact, a fork of Snapmaker’s fork of OrcaSlicer, which is itself forked from Bambu Slicer, which forked off of PrusaSlicer, which originated as a fork of Slic3r. Some complain about the open-source chaos of endless forking, but you can see in that chain how much innovation it gets us — including this technique of color mixing by alternating layers.

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3D Printering: That New Color Printer

December 3, 2025 by Al Williams 15 Comments

Color 3D printing has gone mainstream, and we expect more than one hacker will be unpacking one over the holidays. If you have, say, a color inkjet printer, the process is simple: print. Sure, maybe make sure you tick the “color” box, but that’s about it. However, 3D printers are a bit more complicated.

There are two basic phases to printing color 3D prints. First, you have to find or make a model that has different colors. Even if you don’t make your own models (although you should), you can still color prints in your slicer.

The second task is to set the printer up to deal with those multiple colors. There are several different ways to do this, and each one has its pros and cons. Of course, some of this depends on your slicer, and some depends on your printer. For the purposes of this post, I’ll assume you are using a Slic3r fork like Prusa or OrcaSlicer. Most of the lower-priced printers these days work in roughly the same way. Continue reading “3D Printering: That New Color Printer” →

Tinkercad In Color

October 22, 2025 by Al Williams 4 Comments

Tinkercad is famous for having lots of colors in the interface. But once you export an STL, that file is notoriously monochrome. If you are printing with a single color printer, no problems. But if you have a color printer, what do you do? [CHEP] shows some options, including a relatively new one, in the video below.

The simple way is to “paint” the STL inside your slicer. But as [CHEP] shows, that is a pain and also has some undesirable side effects. A better approach is to export each part (or, at least, each part of the same color) into separate STL files, which you can then import together in the slicer. You still have to paint, but you don’t have to select different faces, and the resulting coloring is more what you’d expect.

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SLM Co-extruding Hotend Makes Poopless Prints

October 13, 2025 by Tyler August 17 Comments

Everyone loves colourful 3D prints, but nobody loves prime towers, “printer poop” and all the plastic waste associated with most multi-material setups. Over the years, there’s been no shortage of people trying to come up with a better way, and now it’s time for [Roetz] to toss his hat into the ring, with his patent-proof, open-source Roetz-End. You can see it work in the video below.

The Roetz-End is, as you might guess, a hot-end that [Roetz] designed to facilitate directional material printing. He utilizes SLM 3D printing of aluminum to create a four-in-one hotend, where four filaments are input and one filament is output. It’s co-extrusion, but in the hot-end and not the nozzle, as is more often seen. The stream coming out of the hot end is unmixed and has four distinct coloured sections. It’s like making bi-colour filament, but with two more colours, each aligned with one possible direction of travel of the nozzle.

What you get is ‘directional material deposition’: which colour ends up on the outer perimeter depends on how the nozzle is moving, just like with bi-color filaments– though far more reliably. That’s great for making cubes with distinctly-coloured sides, but there’s more to it than that. Printing at an angle can get neighboring filaments to mix; he demonstrates how well this mixing works by producing a gradient at (4:30). The colour gradients and combinations on more complicated prints are delightful.

Is it an MMU replacement? Not as-built. Perhaps with another axis– either turning the hot-end or the bed to control the direction of flow completely, so the colours could mix however you’d like, we could call it such. That’s discussed in the “patent” section of the video, but has not yet been implemented. This technique also isn’t going to replace MMU or multitool setups for people who want to print dissimilar materials for easily-removable supports, but co-extruding materials like PLA and TPU in this device creates the possibility for some interesting composites, as we’ve discussed before.

As for being “patent-proof” — [Roetz] believes that through publishing his work on YouTube and GitHub into the public domain, he has put this out as “prior art” which should block any entity from successfully filing a patent. It worked for Robert A. Heinlein with the waterbed, but that was a long time ago. Time will tell if this is a way to revive open hardware in 3D printing.

It’s certainly a neat idea, and we thank [CityZen] for the tip.

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Full Color 3D Printing With PolyDye And Existing Inkjet Cartridges

December 28, 2024 by Maya Posch 35 Comments

The PolyDye system installed on an Elegoo Neptune 2 printer. (Credit: Teaching Tech, YouTube)

Being able to 3D print FDM objects in more than one color is a feature that is rapidly rising in popularity, assisted by various multi-filament systems that allow the printer to swap between differently colored filaments on the fly. Naturally, this has the disadvantage of being limited in the number of colors, as well as wasting a lot of filament with a wipe tower and filament ‘poop’. What if you could print color on the object instead? That’s basically what the community-made PolyDye project does, which adds an inkjet cartridge to an existing FDM printer.

In the [Teaching Tech] video the PolyDye technology is demonstrated, which currently involves quite a few steps to get the colored 3D model from the 3D modelling program into both OrcaSlicer (with custom profile) and the inkjet printing instructions on the PolyDye SD card. After this the 3D object will be printed pretty much as normal, just with each layer getting a bit of an ink shower.

Although it could theoretically work with any FDM printer, currently it’s limited to Marlin-based firmware due to some prerequisites. The PolyDye hardware consists of a main board, daughter board, printed parts (including inkjet cartridge holder) and some wiring. A Beta Test unit is available for sale for $199, but you should be able to DIY it with the files that will be added to the GitHub project.

Even for a work-in-progress, the results are quite impressive, considering that it only uses off-the-shelf translucent filament and inkjet cartridges as consumables. With optimizations, it could give multi-filament printing a run for its money.

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Multicolor Resin Prints: Give It A Shot

February 20, 2024 by Al Williams 9 Comments

[Thomas TEMPE] has been making two-color resin prints. While printing in multiple colors is old hat for FDM printers, the way resin printers work makes it a more difficult proposition. [Thomas] has a simple solution. First, he prints an item with a cavity where he would like the second color. Then, after printing, he fills the cavity with a different color resin using a syringe and cures it. Simple, really.

Of course, it is all about technique. For fine lines, you’ll want a smaller needle, and you flood the area with the alternate resin and wipe away the excess. For wider lines, you simply fill the cavity from a larger syringe.

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A 2D Image Makes A 3D Print

September 15, 2022 by Ryan McConnell 2 Comments

When you imagine 3D printed art, it’s easy to envision the different kinds of sculptures and figurines posted online. While these projects take plenty of time and creativity on their own, [César Galera] shows us a different way to make 3D printed art by turning 2D images into fully textured 3D prints.

This project follows a similar technique that stems from lithophanes, which produces an image from light that passes through the object. [César] instead details in the video below the break how to use the ItsLitho tool to build completely opaque black and white images using a multicolored printer.

Lithophanes are built (or printed) by mapping topography to make light easier or harder to pass through in certain places. Areas that appear darker are thicker with more layers, and areas that appear lighter have less. It’s a nifty optical illusion, but these kinds of art blocks aren’t actually multicolored themselves.

The trick is to develop the 3D model using the lithophane tool first to create the different elevations (ensuring that the lowest elevation is still thick enough to be opaque), but retain the different colors on the model when it’s exported. Multi-colored 3D printers will then be able to add gray and black filament as it prints higher and higher elevation. If you don’t have a multi-colored printer, you can add pauses on the 3D print file to switch out filaments after a few layers to achieve a similar effect.

We’re always on the lookout to see the different things we can print, and being able to turn digital artwork into a 3D model is a great example!

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