Real-Time Physics Simulation Forum

Hi Erwin, I should have reported back on this, but I've been a bit busy. In actual fact, Bullet is working perfectly, it was my mistake(s) (as usual I imagine!) I had a couple of issues, ranging from a slight ordering problem with my debug rendering transformations through to not quite understanding...

Hello, I am unsure if this is possible using Bullet, however I am trying to produce a simple simulation whereby some rigid bodies (spheres) are "trapped" inside a soft body. The closest analogy for this I can think of is a balloon filled with ball bearings. I have studied the softbody demo...

OK, I have performed some more tests and its quite revealing! I have re-done the tests from the uploaded frameworks in order to make everything fair and equal. So I have ensured that for all tests I am using a SaP broadphase (set to single rather than multi in PhysX). The first graph is as before, s...

I'm not sure that this is a very fair performance test for the engines! Engines will be optimised for more than one body, and also probably for bodies in contact rather than unconstrained. For example, when I run the PhysX test case I get timings of around 0.07ms, for one sphere falling. However, t...

In case anybody is interested to see the graph of my results, I thought i'd attach it to this post. http://img225.imageshack.us/img225/2122/peintegrationtiming.png This was produced using the three test frameworks included 2 posts up, with a fourth added created using a very simple little RK4 integr...

Ok, have attached the three frameworks, apologies that the timing code uses a windows header. It was given to me by a colleague and I have used it elsewhere in my work, so I just keep using it to be consistent. I know its not the best way to take critical timings, but it should at least produce comp...

Ok, I made sure that I hadn't compiled Bullet with debug info enabled, and although I was positive i had disabled it, the libs I produced this time round were half the size. ODE and Bullet are now more comparable, with ODE mostly producing figures in the region of low e-06 and high e-07 and bullet m...

Hi Erwin,

Ok thanks, I don't actually have my test beds at home, they are on my office laptop, so i'll have to get at them tomorrow.

I'll make doubly sure I'm not doing something silly, and then clean up the three frameworks and upload them.

Thanks again.

* ADMIN split topic, originally started here: http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?f=9&t=5477 One of my other Vs comparisons has been the processing time taken for each time-step of each engine. i have tried to make each scenario as simple and therefore as similar as possible for...

Sorry for the late reply, Thanks for the response Erwin. With a bit of fettling I have managed to get Bullets response to be very similar to both PhysX and ODE. Rather than starting a new thread, I have a slightly different question I was hoping that somebody may be able to answer. * ADMIN split top...

Hi guys, Thanks to both of you, things are now looking more sensible. Dirk: You're right, I had forgotten that you can modify the way that values are combined in PhysX, by default it (and I assume ODE given the similar results) uses an average value of the two materials restitution (same for frictio...

Hi everyone, I am currently doing a few small comparisons against the main engines (as you do) and have come across something quite unusual. I'm assuming (hoping) that I am making a silly mistake, but for the life of me I can't see it, so hoped one of you might be able to. I have a very simple scena...