Filament Purge to Surface Gradient

[hexsmith]

An idea occurred to me the other day as I was calibrating my filament purge volumes: The change between one color and another during filament swap and purge is likely fairly predictable. If a model was generated in such a way as to contain RGB color data for specific desired elements (e.g. colored surfaces, transparent windows, etc.), the slicer may be able to assume (with properly calibrated purge volumes) that a specific shade of color may be fairly close to the color of filament being extruded at a specific point in the purge process.

All this is to say that it may be possible to produce colors in between primary filament colors by modulating the filament being used and at what point in the gradient purge process the nozzle is currently extruding.

I think this would be best tested with some custom Gcode, and if it can be made even remotely reliable, it should be incorporated as a way to reduce filament waste.

I also think it would be interesting to see if you can reliably generate a moderate blend of, e.g. PETG and TPU. In a purge calibration, I have noticed that the middle of the gradient has interesting properties such as being more rigid but still stretchy. Using filament swap to dither the filament being used and achieve a mix of colors/materials could open up possibilities for creators.

I'm sure it would be a chore to add this as a feature, but if someone could generate Gcode that produces, for example, a RGB lithopane, it could serve as a proof of concept.

Thanks for reading!