A good way to save material support (PVA is quite expensive) is using the second extruder just for the interface.
This option is useful when the supports are only in the bottom of the model. But when the supports are built ON the part, there's no interface. So it's hard to remove those supports without harming the printed part.
It would be useful to consider the interface not only as the inferior intersection between the supports and the model, but for all the external surface.
Use support material interface extruder for layers above object's top…
… surfaces too. #1939
Okay, I implemented this. Thank you for the idea!
Apply contact distance to first support layer above object's top surf…
…aces too. #1939