Real-Time Physics Simulation Forum

You can think of Baumgarte stabilization as a spring + damper. However, if used properly, a Baumgarte stabilization can be stiffer than a spring while being stable.

Erwin, thanks for the picture.

It seems that the number of local minima decreases as penetration becomes shallow. Perhaps this be exploited. Also during deep penetration the exit direction may not matter much (it won't be pretty in any case).

It is unclear how these observations carry over to 3D.

You can read about non-convex optimization on this page: http://www.solver.com/probconvex.htm If you want to learn more about optimization, I recommend this book: http://www.amazon.com/Numerical-Optimization-Operations-Financial-Engineering/dp/0387303030/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1...

Please, may we discuss this problem? I'm finding fast enough incremental alghorithm and local vs global convergence is its weakness. What is your question? Like I said, I don't think this algorithm will work. It is basically a separating axis test with a local search. Local searches for the minimum...

Hi Kenneth, This looks really nice! A had phun playing with it. :) Will this project become open source? Will your team be publishing technical details on the implementation? What are you using for the concave collision? The stacking looks quite stable. Are you using any sort of shock propagation an...

Relative damping should work ok.

However, damping wouldn't support static rolling/spinning friction. You may want a ball to stop rolling on mildly flat surfaces.

Yeah, you could use relative angular damping.

How about just using this velocity constraint: omega2 - omega1 = 0 And use a maximum torque for this constraint of: torqueMax = roll_spin_factor * choose_a_length_scale * sum_of_normal_forces. You can safely use this in all cases, even with multiple contact points. So you wouldn't need to detect rol...

You can use a conjugate gradient solver (Google GPCG).

You can also form the associated LCP problem and use a pivoting solver like Lemke's method.

Hi David, I'm sure many people here would be curious to know about the inner workings of Tokamak. I used the algorithm describe in this paper http://www.cs.hku.hk/research/techreps/ ... 005-01.pdf (Collision Detection of Convex Polyhedra Based on Duality Transformation). The algorithm seems sound, b...

Alessandro, I scanned over this paper. Some of the math is a bit deep and I didn't spend the time to digest it all. How would you compare this method to Bullet's sequential impulse solver? Does the CCP provide you with isotropic friction? Is that the main advantage? The paper states that the solver ...

Is there any reason why I couldn't just save the contact points in untransformed object space for each contact, and then comparing against those when getting the new set of points, instead of the feature info? (I mean, other problem than having to compute the inverse transform of the objects for ea...

How are you matching contacts for warmstarting? Is the translation disrupting warm starting?

Are you warm starting friction and normal impulses?

Ahh. Yeah, for cloth constraint ordering can make a big difference, especially if you use a stability factor as in Andrew Megg's cloth presentation.

https://www.cmpevents.com/GD05/a.asp?op ... essID=3931

When I was studying constraint ordering, I would simulate a stack of boxes or a chain and export the MLCP to a text file and load it into Matlab. It was quite easy to try different orderings and measure convergence. You may get better results, but the best I could do was shave off one iteration. In ...