Fabrizio, I have some more info on this. I think this issue is due to your Windows->Settings->System->Display->Advanced Scale Settings->Custom Scaling is not set to 100%. This issue is resolved in the next release of the Rhino6 plugin, but in the meantime, changing this scaling back to 100% should get you operational.I tried to install the last version of octane for rhino 6. I have some trouble with slider and values of material node. Is it an octane problem or rhino 6 problem?
Paul