Cancel specific objects during print

[danilius 117]

No idea if anyone has suggested this already, but I would love to have some way to be able to top printing one or more objects in a multi-object print if they have failed somehow during the print.

[nallath 667]

This isn't possible due to how g-code works. The machine has no idea what one object or the other is.

[ahoeben 707]

Well, in theory comments could be placed in the gcode showing where different objects start, and the firmware could just skip gcode from the start-comment of such an object until it encounters a new start-comment for another object. But that would be a non-trivial change to the slicer and to the firmware.

[nallath 667]

And you would be depending on comments to ensure that it works, which is kinda nasty.

[danilius 117]

I was thinking along those lines. I fully appreciate that this is non-trivial, but it is nonetheless jolly useful.

This would of course could break Marlin in a big way, but perhaps not so drastically. As it is, the whole gcode thing is a bit long in the tooth for 3D printing, but assuming that we want to stick with it, one could add some very simple features into the firmware to handle this.

For example, bracketing each layer of each object with a start/end marker in comments as @ahoeben suggests. Standard firmware will simply ignore these comments, updated firmware will understand what they represent and could, upon receiving a custom gcode, simply skip to the next object on that layer.

Of course each object will need label, which could be set and/or autogenerated in Cura.

Maybe this is something for @Tinkergnome to play with?