I am browsing sketchfab.com for assets and some of them are 'CC Attribution' which means you must attribute the author in your work. Where would I put this information in my game? Especially if I am using many assets. Do I have to attribute each author individually or can i just say 'some assets from sketchfab.com' for example?
The CC-BY license requires that you credit the author of the work, not the platform that conveyed it. So yes, when you take lots of assets from lots of different creators, you must credit each of them in the way their individual license conditions demand. Which in the case of the Creative Commons, means with the creators name, the name of the asset, link to the asset and a link to the license. Otherwise you are committing a copyright violation. Which means that the creators of those assets might cause you all kinds of problems. Like sending DMCA takedown notice to the platforms through which you sell your game or even sue you for damages.
General practice for giving credits is the credit screen of your game. Which should, according to the guidelines by the IGDA, be easily accessible from within your game without having to play the game itself. Yes, game development tradition is to show the credits roll after "beating" the game (whatever that means in the context of the game your are making). And I personally am actually a huge fan of this tradition. But due to the requirement to make credits easily accessible, you usually also make them accessible immediately through the start screen or options menu.
My personal approach when dealing with 3rd party assets is to create a text file for each asset I download that contains the credit message as demanded by the license conditions, name it like the asset and store it in the same directory. Not to include those in the final build, but for myself so that I remember what credit I need to give for each asset when I make the credits screen later (which you might even be able to automatize with a script). When you don't keep track of where your assets came from, then you might years later find yourself in the uncomfortable situation that you have to search every single asset site you can think of for hours to again find that !#$%& grass texture you used so you can credit it appropriately.
Exact terms will vary depending on the particular variant of CC license involved.
Generally speaking, you will need to include, for each individual asset:
- a copyright statement; and
- a link to the material; and
- the terms under which use of the asset is granted; and
- this may entail either inlining the full license text or simply providing a hyperlink to it
- the author's name (may be included in above).
Some versions of the license may require inclusion of the asset's name in addition to or instead of a hyperlink.
Attribution should be reasonably visible (technically "reasonable to the means, medium, and context of use"). In the context of game-dev, this often means including credits accessible from the title screen, launcher, or alongside a readme.
You can learn the specifics for each particular CC license at the Creative Commons website.
The Creative Commons site also provides examples on how attribution should be given:
This is an ideal attribution because it includes the:
Title: “Furggelen afterglow”
Creator: “Lukas Schlagenhauf“—with a link to their profile page
Source: “Furggelen afterglow“—with a link to the original photo on Flickr
License: “CC BY-ND 2.0”—with a link to the license deed