Blender's stance on the free nature of the project and paid GPL add-ons
Ton Roosendaal, the creator of the 3D modeling system Blender, has published an assurance that Blender has always been and will always be a free project, distributed under the copyleft GPL license and available without restrictions for any use, including commercial applications. Ton emphasized that all Blender developers and those creating plugins that utilize the internal API must open their code.
