Armatures and Physics: Where do I start?

How do I simulate physics on objects with armature modifiers?
How do I blend between keyed animation and simulated frames?

Been searching around for sometime, but haven’t found an answer yet.

Depending on the simulation in play, a weighted vertex group can be used to control how much a mesh responds to physics. If the mesh is not under 100% physics control then it can be influenced by other means such as an armature. Example: the Cloth sim’s Pinning Group – a weight of 1.0 on a vertex in this group = no cloth response; weight = 0 means full cloth response (and only cloth). Intermediate weights give partial response, allowing for other influences simultaneously.

That’s a bit more complicated. Generally, the physics sims operate from cached data rather than keyframes, so a direct transition isn’t possible. The vertex weighting isn’t animatable afaik, so you can’t really fade the sim influence that way. Some physics animation can be converted to shape keys (Cloth being one example) so that’s an option for blending with other keyed motions. A more complicated but nonetheless effective transition method is to render the sim-controlled mesh up to a certain frame, then swap it for an identical mesh that is not under physics control, and can be keyframed as needed. Can’t do a blended transition though, so it’s got limitations.