Julio (Newton author) on physics comparisons/COLLADA Paper

[Erin Catto]

I can see that you, like Mr Kenb, have a great deal of confusion with Gyroscopic forces stuff, I am going to recommend to you to read my post about how to reproduce, http://www.physicsengine.com/forum/viewtopic.php?t=3746

Julio, you might want to check your dynamics books again. You have a obvious sign error in your formula.

You wrote:

D(R)/dt * I| * W| = W~ * R * I| * W| = - R * W|~ * I| * W|

But the last equality is wrong.

Now:
W~ * R = R * W|~ * transpose(R) * R = R * W|~

So instead of:

T = -R * W|~ * I| * W| + I * A

You should have:
T = R * W|~ * I| * W| + I * A

You might want to fix your post so that people don't try your solution and incorrectly judge your engine to be unstable.

[Antonio Martini]

I am not asking for any consideration from, quitefrankly I do not really need it from anyone here. [...]

really no time for arguing about your illogical behaviour and going through your silly considerations. I was just trying to give you some constructive advice given that you really seem to be in a lot of pain. It was meant to be a suggestion not an attack. It appears to me that your problems belong to fields that have nothing to do with physics and as a such you are totally off topic.

actually you have misleading statements on the home page of your own engine :

"Our engine implements a deterministic solver, which is not based on traditional LCP or iterative methods, but possesses the stability and speed of both respectively. This feature makes our product a tool not only for games, but also for any real-time physics simulation."

a solver with quadratic complexity doesn't offer the same speed of iterative methods as you have been claiming for years on your home page and you also seem to admit now after it was obvious from the published complexity plots.

Antonio

[Eternl Knight]

I would respond properly to some of your personal (as compared to rational or technical) comments, but as you have been banned from posting - I will refrain from doing so.

I will mention my regret that you could not discuss things civilly, because (regardless of my personal issues with you) I believe you are quite knowledgeable in the field of simulated physics engines.

--EK