Arachne engine beta

This is the beta release of Ultimaker Cura's "Arachne" engine. The objective is to fill the available space better with walls, reduce variability in flow rate, preventing gaps and overextrusion and improving path planning by implementing variable line widths. This allows for a more consistent print and better fit to the specifications of the original 3D model.

This is an outdated beta. Please refer to the Arachne engine beta 2

If you've tried this beta and want to give some feedback, please see the discussion here.

This is a second preview, bringing the engine to a more stable state than the alpha that was released in December. This release should be more appropriate to tune profiles within preparation for the stable release. The stable release will still have its own beta in the same fashion as the ordinary release cycle.

While the bugs and features that greatly influence print quality have been resolved and implemented, there are still some things left to do (see known issues). The profiles have hardly been tuned, even for Ultimaker's own printers. Please don't expect perfection. In fact, the default settings as they are now likely result in a worse print quality than the stable release.

Note: This is not based on a specific stable version of the front-end of Cura (like '4.8.0' or similar), so there may be issues that have been solved or introduced since then that have little or nothing to do with the variable line width feature-set!

New features in Arachne engine beta:

Line Width Color Scheme
A new color scheme has been added that shows the line width of individual lines in layer view.

Static Outer Wall
The outer wall will no longer adjust its width or position if there are any inner walls adjacent to it with the (inward) distributed line width strategy. This reduces ringing effects in thin shapes.

Bug fixes

• The Randomize Infill Start setting is now working on Arachne.
• The Infill Travel Optimization setting is now working on Arachne.
• The Infill Layer Thickness and Support Layer Thickness is now working on Arachne.
• Fix crash on MacOS when printing parts with a single wall.
• Fix crash when the model contains very small holes (~0.1mm).
• Fix crash when using Support Infill.
• Fix crash when the model contains faces that are almost exactly parallel.
• Fix crash when simplifying due to Maximum Resolution causes self-intersections to appear in the layer outline.
• Fix crash when multiple transitions come together in the same point.
• Fix crash when transitions between different numbers of walls connect the wrong two perimeters together.
• Infill and support layer thickness should no longer overlap with itself if gradual infill or gradual support is used.
• Only generate connecting wall segments for the sparsest density when using gradual infill or gradual support.
• Sharp corners in the infill volume will no longer be filled with a useless tiny infill line.
• Initial Layer Line Width now only applies to the initial layer again.
• When using Outer Wall Inset, there will no longer be a ridge when transitioning from 2 to 1 wall.
• Outer Wall Wipe Distance will no longer cause unnecessary travel moves.
• Concentric support interface patterns are no longer omitted.
• When Wall Line Count is 0, the rest of the model will no longer be omitted.
• When using different extruders for inner and outer walls, the extruders no longer alternate per layer.
• Small gaps between inner wall and skin are properly filled with infill again.
• Seam position when using Sharpest Corner set to "hide seam" now properly chooses the sharpest inner corner.
• Transitions are no longer omitted in very sharp corners, which sometimes led to too small line widths.
• The outline of the print is no longer shifted towards the bottom left by the Maximum Deviation setting.
• When using Alternate Extra Wall, the extra wall no longer overlaps with skin or infill.

Known issues

• Some models might still crash the engine, although it is less frequent than before.
• Infill support can crash the engine.
• The seam isn't positioned correctly when using the Hide or Expose or Smart Hiding placement options.
• User specified seam is not aligned.
• Paths for concentric ironing aren't generated.
• Concentric support pattern can intersects with model.
• Lines are not always symmetrical in width at the transitioning point to a lower wall count.
• Centerline is not generated for center deviation strategy.
• Missing infill/support walls in certain areas when using Extra Infill/Support Wall Count.
• Brim lines ordered wrongly.
• Raft interface layers and raft layers don't align.
• Connected infill and gradual infill results in overextrusion.
• Bottom Skin Expand Distance at zero causes skin to expand beyond walls.
• Spiralize could generate both inner and outer surfaces.
• Bottom layers of a spiralized model with surface mode enabled, looks like inner walls.
• Last bottom layer might disappear for a spiralized model.
• Stringing when spiralized is enabled.
• Fuzzy skin isn't implemented.
• Connect Top/Bottom polygons isn't implemented.