Get an engine boost with Ultimaker Cura and Arachne beta

The Ultimaker Cura slicing algorithm has been enhanced with the Arachne code library. This fundamentally changes how Ultimaker Cura handles inner parts of a model. As such, we want your feedback – after you try it in a special beta version of Ultimaker Cura, which you can download below.

Let’s say that you want to print within a 4.4 mm-wide space. Using the current slicing engine, a constant 1 mm line width could leave a 0.4 mm gap that would be tricky to fill.

Here’s where Arachne comes in, adding a variable line width to the slicing algorithm. That could mean printing 1.1 mm across all four lines to ensure good fill and prevent the 0.4 mm gap.

In this way, we intend the upgraded slicing engine to optimize line positioning and variable line widths – especially for thin walls and around corners.

This should result in:

  • Better handling of thin walls and filled gaps  

  • Smooth line transitions inside tapered geometries  

  • General print quality and strength enhancements  

  • Reduced print head movement for filling in gaps

Ultimaker Cura 4.8 stable
Ultimaker Cura Arachne beta

Which new settings need testing?

The improved Ultimaker Cura engine gives you new settings that will optimize printing thinner walls, including:

  • Variable Line Strategy (3 options: Center Deviation, Distributed, Inward distributed)

  • Minimum variable line width

  • Wall transition length

  • Wall transition angle

  • Wall transition distance filter

Now you have the chance to peek into Ultimaker Cura’s future, test these settings, and see how they work for you!

Ultimaker Cura 4.8 stable
Ultimaker Cura Arachne beta

If you decide to tune these settings and doing so results in better print quality, please share your findings with us. Doing so will help us set default values for both Ultimaker and third-party printers.

How to start testing

Before sending feedback…

During the beta test, we will keep this support article.

Please take a look before you post a bug report. This will prevent extra work on your end and ours.

We're incredibly excited about what the Ultimaker Cura engine improvements will offer the global 3D printing community. And by working together, we will be able to turn it into the best possible version for everyone.

Download the beta