Screw-on FilaScope for HueForge

Important note: On June 27th, 2023, Steve from HueForge released a new “step test” to check the Transmission Distance. I made a remix for it, that can be found here at Printables; there you can find more about this new test, my take on it, and how does it compare to the FilaScope. Thanks.

What is this?

If you already know Hueforge, you can go to the next step. Thanks.

Well, HueForge is a program that cleverly helps you make multi-color prints, in unique colors, without needing a device such as a MMU, AMS, Palette and whatnot; it does everything just by z-based color change and color blending. The “blending” part is where HueForge really shines, as it's a complicated thing to do but can give amazing results.

To get good results you need to have measured previously the light transmissivity (aka “opacity”) of your filaments against a light source. And Steve Laveda from HueForge, who has a wizard-like name and probably is, quickly pulled out the FilaScope: a tool to do exactly that, with sample disks of different thicknesses.

Thing is, I didn't quite like that the disks weren't secured, so I made this in order to have a two-part tool that allowed firmly setting the disks in place, looking up to your ceiling lamp, and had some kind of light trap.

(Personally, I also don't like the name “transmissivity”, either; I would have gone with Terminator, not only for the cyborg but also for the “twilight zone” of a planetary body, where light and dark meet. But that's just me.)

How does this work?

This Fila(mento)Scope has two parts: a “base” and a "visor". Disks are placed in the base, inside the screw thread, and then the visor is screwed in place.

Thread is a 4-start, trapezoidal 45-degree section, chamfered ends, hefty 5mm-pitch one, with 0.15mm thread allowance. It will lock with just one-half or one full turn. If you have trouble locking it, I suggest putting the two pieces together, applying gentle pressure, and do like un-screwing it. At some point, you'll notice how they “fall” in place, and then it's time to close.

What are all those variants?

First, an important note: you'll need to print parts of the same wall thickness, otherwise they won't fit. All parts of the same wall thickness will fit well.

The variants are:

• Wall thickness:  There are 3 variants: the original thick (5mm) walls and the newer thin (2.5mm) walls of the original FilaScope, and a new medium (3.75mm) walls for Goldilocks reasons.
• Base shape: There are 2 variants: the same rounded, bell-like shape of the original FilaScope, or another conical one, that saves material. 
• Thread length: Usually, the short 10mm thread will work for most, if not all, opaque filaments. Translucent filaments are something else, and may need the long 20mm thread. Note that if you need to put all disks to measure transmissivity, you'll eat about 10mm of thread, so the short one won't lock at all. If in doubt, just print the longer versions, and if you don't plan to use translucents, go with the short; you can always print a longer-threaded base later.
• Visor length: The original, long, 56mm and newer short 36mm from the original FilaScope, plus another 46mm medium one because… yes, Goldilocks is pretty determined some times. The medium-wall, short-length visor will likely require supports (the only piece to do so), and there's no thick wall, short visor (simply wouldn't fit…).

Final notes and warnings

The thread will require a well-calibrated printer. You may make yourself a test piece by cutting the in/out threads of two parts with the “Cut” tool in a Slicer, which doesn't have to be your favourite one. (I mean, you can quite like Cura and that's perfect, but the new “cut” tool in PrusaSlicer is great, so there's nothing wrong in using PrusaSlicer not to slice, but just as a quick & simple 3D editing program).

Print in black. This will help avoid backlighting and other lighting effects. I've used matte black PLA myself, but you don't have to.

You may want to set ironing to topmost surfaces for the base. This can yield a very flat top for the disks to lie on, and a very flat screw thread top (which isn't that important, as the visors have a 45-degree angle section joining the screw and inner tube). But having a flat surface for disks can prevent lighting leakage. (If ironing gives you trouble, I made a parametric calibration model that might help.)

Please refer to the original FilaScope for additional instructions on how to use.

The models are made in OpenSCAD. The only reason I haven't published the source code (yet) is because they are in the spaghetti hell of dependencies from libraries of mine. What I mean is that if you need/like some tweaks/variants, that may be something pretty easy for me to do, and all you've got to do is ask.

The box in the pictures can be downloaded from here at Printables.

Have fun, and forge amazing hues!