Animating separate objects / items independently in the same action I'm creating a web-based presentation which walks through ± 5 different subjects. Each subject is accompanied by its own infinitely looping 3d animation. When switching between subjects, the animations should seamlessly transition between each other, similar to switching between different walk cycles (idle =&gt; walk =&gt; run =&gt; walk =&gt; idle, etc.). Each animation is composed of several different objects.
Three.js allows for cross-fading between different actions. My plan is to create an action for each subject and cross-fade between them.
In Blender, I tried to animate (as an example) the Z-location for separate objects which were linked to the same action. However, once a parameter for one object is changed, it appears to affect all objects sharing the same action.
How to independently animate separate objects within the same action? Or should I go another route and animate other entities such as vertex groups, lattices, ...? Just started out using Blender, any kind of guidance is much appreciated.
Blender Actions can't have different effects on different objects.  So, if you want an entire character to be managed by a single Action, it needs to be a single object — or at least linked to a single Armature. Assuming you're exporting to glTF to bring these models into three.js, you may find the exporter documentation on animation useful. Multiple NLA Tracks with the same names will be exported as a single animation, even if they affect multiple objects.