Ok. I’m closer to the problem and fixed it for me.
It looks like the PWM output doesn’t work at Lightburn as long there is no material database available. After adding a material database the fill dialog changed with also an option for flood fill. I have tried again with this option and now anything works as expected. Also if the flood option is not used now anything works as it should.
Attached a picture of the changed dialog the old version is shown in the previous post. Maybe someone of the Moderators can confirm.
It’s really strange to me. I found another user who solved this using the flood fill option. Again: After adding material database and using the option it looks like it now works all the time perfectly.
