I found on a tutorial on internet a easy way to loop every single animation for every object. Apparently , click on the object on the animation timeline, on the attribute manager should display a option called loop. However in cinema 4d 12 does not show up. Any idea where could be?
That tutorial was for R9. Since R10, there are options in a track's Attributes Manager named "Before" and "After". Their default is set to "Constant". If you want a looping animation, set it to "Repeat". You can have it repeat either Before, After or both depending on how you need the animation to loop.