Source: Biqu

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TD Time

Biqu’s New RGB Color and TD Sensor Will Make Matching HueForges a Lot Easier

by Shawn Frey
Published May 23, 2025

The collaboration will see Ajax 3D's useful sensor readily available off-the-shelf, and in a much smaller package.

Biqu, in partnership with Ajax 3D, is launching the TD1s: an RGB color and Transmission Distance (TD) sensor that reports a filament’s hex code and TD value by simply passing it through like a filament-runout sensor.

The device is a refined version of Ajax 3D’s TD-1, a kit device that was released in fast-selling limited runs explicitly for use with HueForge – a “filament painting” application. Biqu and Ajax worked together for a year to develop this new version of the product, and Biqu says it will release with an updated firmware. There are plans for deeper integration, too, as Biqu says it’s working with the teams from Klipper OS Mainsail and Orca Slicer “to bring native TS1s integration”.

If you’re not already familiar with HueForge, RGB and hex codes are probably what stand out to you, but TD is the more important number here. It’s a measure of how opaque a filament is, and how well light is able to pass through it. With that unit, the HueForge software can determine how well the colors of one layer over another will blend and create the desired tone on the final layer. Hex codes are, of course, important for that too, but there are other ways to collect that information, and manufacturers like Polymaker, with its Panchroma sub-brand, are placing increasing importance on hex codes and consistent color production. But TD is more difficult.

A TD-1 next to a prototype TD1s (Source: Ajax 3D)

“TD was a data point that no filament manufacturers were testing for or even mattered before HueForge. TD was difficult enough to understand let alone test right,” Ajax 3D says on its website, “I decided there needed to be a better way to acquire the information. So I created TD-1 to eliminate all the test swatches, light boxes, and confusion about what you were even looking for.”

But, Ajax 3D is a one-man show. Assembled products were rare, and kits were $40 if they were in stock. Self-sourcing from a BOM has been common.

Now, Biqu is filling in the supply chain with a smaller unit and an injection-molded case, with firmware changes that it says improve performance. The result is a TD accuracy of +/-7.5% for $80. On par with the assembled TD-1’s original retail price, but higher than its kits. If you’re popping out a lot of HueForge prints, it’s probably worth the cost of entry.

The TD1s is available for pre-order now and will begin shipping on June 30.

Update – May 27, 2025: Added additional context regarding the original TD-1 price.

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