Thanks for the follow-up, it is interesting to see how&#x2F; or not the GPL works in areas other than code.<p>So redesigning from scratch, following strict clean room protocols (fresh designer who hasn&#x27;t ever worked on the GPLed design, given a description only), defeats the GPL because it is based on copyright ?<p>Presumably no GPLed RepRap derived community innovations were copied, if they were ( hypothetically an amazing way of doing the nozzle or special hot-plate method to avoid warping ) would this demonstrate a derived work and trigger GPL ?<p>If this type of thing isn&#x27;t a GPL trigger then why can&#x27;t anyone clean room a different design of sintering tech and allow general sinter 3D printing and sales ?<p>Is this difference because the GPL relies on copyright but 3D sintering is patent protected ? If so does Open Hardware need a GPL patent license, can that even be possible ?<p>Has a hardware GPL case ever been brought ?