TL;DR: what "no copyright" means
A work has no copyright only if its protection has expired, it was never protectable, or its owner gave the rights up. That covers the public domain (in the US, everything published before 1931), US federal government works, ideas, facts, names and basic shapes, purely AI-generated output, and works the owner released under CC0.
Most things sold or shared as "no copyright" are something else: royalty-free or Creative Commons material that is still protected and comes with a licence. And writing "no copyright intended" under a video has no legal effect at all. This guide explains each meaning, shows 3D and Blender examples, and gives you a five-step check before you use anything labelled "no copyright" in your work.
Prove it's yours before someone calls it "no copyright". BlendedBoris is a free plugin for Blender that records your 3D model on the blockchain and gives you a lifetime ownership certificate. It creates a digital fingerprint that links the model to you, so you have dated proof of authorship for every version, ready to attach to a takedown notice when your work turns up on a "free" or "no copyright" site.
👉 Get the free BlendedBoris plugin