Hi, control rigs can be pretty heavy in terms of memory usage. A lot of that is down to the rig hierarchy, so the more complex the hierarchy, the more memory you’re going to end up paying for.
In terms of your specific questions:
> Since every rig seems to have an memory weight of 2mo or more, is it strongly suggested not to use it to do procedural animation tweaks?
This is always going to be a balance between fidelity and performance. Control rig gives you more freedom to manipulate individual bones than you have in an anim bp but, as you’ve seen, control rigs can become expensive both in terms of memory and performance. From a performance point of view, we often recommend disabling execution of a CR when running with LODs at lower detail. But it’s more difficult with memory usage since you’ll either have the control rig loaded or not. You can improve memory usage with control rigs by making sure that the rig hierarchy only contains what you actually need - if there are extra bones, curves, controls, etc, that aren’t required in the hierarchy, you’ll be paying a cost for them in both memory and performance.
> Meta human faces requires a RIG in order to play animation from meta human associated curves, is there a way to make that rig more lightweight from a mem aspect or is there a way to compute the curves without Rig (Like a pose asset of some sort)?
Which of the control rigs were you talking about specifically here? If you aren’t using facial animation generated from MH Animator, you can actually just remove the Head Movement IK control rig from the Face_PostProcess anim bp entirely since it’s only used to apply head movement from MH animator animations. So that might be one option. Even if you do need to use that control rig, you can simplify it like I mentioned above - it contains the whole facial skeleton but, as far as I’m aware, doesn’t actually operate on any of the facial bones so those can potentially be removed.