Real-Time Physics Simulation Forum

I would recommend using the links in the first post to contact them directly, I doubt they are monitoring this forum post.

http://math.ucsd.edu/~sbuss/ResearchWeb ... 11Talk.pdf

That might help if you need more accurate methods. Sam Buss has an older paper somewhere if you want more explanation.

Heh, nice one - thumb's up!

It depends on what you're simulating. For a simple mass-spring system, there is a simple formula for whether it is too stiff for semi-implicit Euler to be stable. IIRC, the oscillation frequency has to be less than half of the physics sampling frequency.

Good point, I agree cylinders might work pretty well.

Not to be nitpicky, but I think you want the word "stretched" not "sketched" - I'm just mentioning this because it took me a moment to figure out what you were saying. Anyway, that's a challenging problem to do well in realtime. I think you'll definitely have to customize your so...

Try your question in the "General Bullet Physics ..." area, you'll probably get a better response.

if you're changing the velocity directly with an impulse, you're changing the energy level. And if it's "stabilizing", it's going to be towards less energy. Reasonable enough and maybe this is what happens in practice with SI but the underlying theoretical principle (if I understand it co...

BTW, I'm not presuming to be sure that's the *only* cause of damping. I'm just not currently aware of anything else that necessarily causes it. For example, SI may also be inadvertently causing it, simply by converging from one side of the "correct" solution.

Good point: my implementation of Baumgarte *is* in a system using force-level acceleration, so the damping is indeed more obvious. I'm not sure it matters that much: if you're changing the velocity directly with an impulse, you're changing the energy level. And if it's "stabilizing", it's ...

I think an answer to the second question may help with the first. Yes, the predicted velocities already handle external forces, but the main problem is that the direction of the constraint (the angle of the pendulum itself) is changing during the timestep, and that's not accounted for in most modern...

I think you'll find even a 'single' pendulum will get damped, because the constraint solver doesn't solve this exactly over the entire timestep, it only solves it exactly at the beginning of the timestep (at least with symplectic Euler integration, but IIRC there exists no integration scheme that wi...

I'm not sure what other people do, but I just consider a single collision as a constraint, to be solved generically along with every other constraint. I suppose that's closer to your global solution.

Ahh, okay, thanks. I misunderstood.

Sorry, which equation number of Hecker's is wrong? Thanks.