Thread by @tonroosendaal

Blender is Free Software. It's free to use for everyone. Free to use for any purpose, also commercially. Blender is free to share with others, free to study its sources and free make new versions.

Blender is free, forever. #b3d

This freedom is what makes the GNU GPL license so powerful and it's why it's much more than "open source". The license simply prevents anyone to put restrictions on Blender. That protects users as well as everyone who contribute to Blender.

If you decide to contribute to Blender, whether as Python script or as C++ code, you have to agree on this freedom. You can keep all rights of your own work, but if you publish or sell or share Blender code, you do it just as Free as Blender is.

The GPL has often be called infectious. I think that's a negative and misleading frame. Proprietary code is infectious in ways too.
Best is to keep the public and open domain entirely separated from your private proprietary domain. And really, both domains can live well together.

You can create bridges between the domains. This is how Blender can work with other proprietary tools or engines. The bridges (if using Blender code) have to be fully GPL compatible. The closed sw such bridges lead to can not be bundled, it's your own concern to connect it.

In the past years, developing and selling Blender add-ons grew into quite a big market. We've all seen fantastic & powerful scripts doing amazing things. Great add-on coders indeed. But also: what an incredible API these C devs made for Blender!

Blender add-ons work, look and feel like Blender features. And as for any other Blender feature that means - it has to be free, free and free forever! Paying for an add-on just means access to the add-on download service... offering it to you as GNU GPL. Your freedom guaranteed.

I've always interpreted Free Software and the GNU GPL as a means, not a goal. It just works fantastic for Blender. I'm not going to blame proprietary programs for not opening up. But I also won't accept proprietary business to pollute our open domain. Live, and let live.

And if you think you 'suffer from piracy' or find it hard to do business with Free Software? Just distinguish yourselves with the proven successful free/open source business model: provide docs, training, content, frequent updates and support. Your customers will love you!

Disclaimer: I'm not a lawyer and not a license expert. Just sharing how I see this complex matter. Hopefully it helps understanding Blender's license better. Thanks for reading!