@d-healey said in Creating sample based instruments using Pianobook?:

I doubt it, unless he gets a proprietary HISE license, otherwise anyone would then be free to redistribute Spitfire's samples.

The samples don't have to inherit the GPL license, as long as they are publicly available, I don't care (and the JUCE guys also won't sue you).

Just ask the Spitfire guys if they are OK with it, then put your instrument project on GitHub, add a link to Spitfires Download site and done.