WARNING: Embedding objects in your print is risky. Mistakes or oversights in slicing could result in collisions between your nozzle and the object!

That said, this sample tea light holder demonstrates some of the interesting effects that are possible when you feel ready to take the risk. See here for video: https://youtu.be/1aovdxwkPn0

This file is designed for 15mm diameter marbles and a hot end with a nozzle that protrudes at least 5mm from the bottom of the heat block. If these aren’t an option for you, don’t try this project!

The clear marbles shown are from Michaels: https://canada.michaels.com/en/clear-lustre-marbles-by-ashland/10556564.html. There is some variability in diameter, so use calipers to select six that are between 14.5 – 15 mm.

Slicing

The recommendations here are for Cura 4.8.0.

Import “Reference Marbles” and “Tealight Enclosure” into Cura. Right click and “Reset All Model Transformations” so that the reference marbles are sitting inside the tealight enclosures where the real marbles will go eventually. You will notice that the reference marbles are on long 0.1 mm diameter “stilts” so that they don’t automatically drop to the build plate when they are imported.

The reference marbles will be used to program “no go” zones for the nozzle, they will not be printed.

Select the “Reference Marbles” and open “Per Model Settings” to apply customized settings to this object. Check “Wall Line Count, “Top Layers, “Bottom Layers” and “Infill Density” and set all of these values to “0”.

In the main section under “Travel,” ensure that “Combing” and “Avoid Printed Parts when Travelling” are checked. The reference marbles are now “ghosts” that won’t actually print, but will be avoided when generating gcode. Slice the file and closely preview a few layers to ensure that the nozzle does in fact avoid the spaces where the real marbles will eventually be placed.