Do "procedurally generated" skyboxes on the Unity Asset Store use machine learning trained on existing images?

Question

I noticed that some skyboxes on the Unity Asset Store specifically say they use AI image models like Stable Diffusion, for instance "Stylized Space Skybox pack":

The description of this asset says:

Created with AI

AI (Stable Diffusion) was used to generate elements for the skybox images. The images were then upscaled with AI and edited to fix seams, artifacts, stretch, and vortex elements. Only generic words were used, no media or artist names.

Meanwhile, other skybox assets don't explicitly say AI, but they do say "procedurally generated", for instance "Space & Nebula Skyboxes"

This asset says:

The Space & Nebula Skyboxes is a collection of 30 procedurally generated, high quality skyboxes. The detail of the skyboxes is amazing considering that each cubemap side has 4k resolution.

I know that AI generated images created by models like Stable Diffusion use training from a set of existing images created by real artists in order to create new images. This might potentially lead to some copyright issue if some real artists are not happy that their original images are used in the training set without their permission.

So I want to know whether I can safely use "procedurally generated" skyboxes that don't specify they were made by AI, or if they are produced the same way.

Answer 1

"Procedural generation" is a broad umbrella that can include any technique that produces content through an algorithmic procedure. There's no hard rule that says that cannot include machine learning algorithms like AI image models, though most uses of "procedural generation" in game development are not talking about that technique.

For example, Unity has a built-in feature called "procedural skyboxes". This is a shader material that runs the math to simulate Rayleigh scattering of light through particles in the atmosphere for each pixel to calculate what colour should be visible in that direction. That's the "procedure" in "procedural" in this case.

Other conventional ways to procedurally generate skybox images would be to use a 3D rendering package to pseudo-randomly scatter bright points for stars, use noise functions to sculpt fake nebulas or clouds, etc. None of these techniques rely on machine learning training from artist-created images.

However, the terminology around procedural generation and machine learning models is not regulated. It would be possible for an asset creator to use an AI image model to produce assets and then not disclose that in the asset description (even if this would go against any relevant terms of service the shop ostensibly enforces - violations happen).

The only way to know for certain would be to ask the creator of a given asset directly. If they reply back in the negative, you could use record of that communication in defense against liability should anyone later claim that your game used AI in a way it should not have: you show you did your due diligence to establish whether the assets were of AI provenance, and even if the creator/distributor lied to you, that's their fault, not yours.

(I am not a lawyer, and this post is not legal advice. To get proper legal advice, consult an accredited expert in your jurisdiction)