How do I make the simulation follow the animation better?

[alanjfs]

Hi @rikk8820, welcome to the forums.

@rikk8820

I’m new to the software and I followed a tutorial on how setup the physics on my character.

Great work, those shapes look great, no notes there.

@rikk8820

however the arms and hands don’t really follow the animation much, they are way too loose

The simulation lagging behind your animation is typically due to the Damping attribute, a higher value means greater lag. It’s there to emulate “friction” or “fleshiness” between limbs. During fast motion, you’ll want to reduce it. But reduce it too much and the character can get all jiggly and robot looking, so it’s a balance much like the Stiffness attribute.

@rikk8820

So the question is, can I move the breast mesh on collision? Like a soft body or something?

Collisions can’t be soft (until the coming release, spoiler) but in this case you may not need collisions between arms and chest. So you can either disable collisions on the chest, or set the character group to Self Collide = Off, or you can assign a Ragdoll → Edit → Collision Group to arms and chest, such that they still collide with other things, just not each other.

@rikk8820

I tried setting the hands as “Animated” but the arm will start moving in weird ways.

Yes, generally, when you have simulated markers between two animated markers you’ll get odd results. There’s no equivalent to this in real life; the animated Markers will apply infinite forces to the simulated Markers between them, ignoring momentum and ignoring limits, including the limit which keeps them connected.

Instead, avoid “trapping” simulated Markers between animated Markers and use a Pin Constraint for things like the head and feet. They will enable you to still follow the animation, and apply the same rules of Stiffness/Damping, whilst still allowing the simulation to preserve momentum and limits.