[ODE] Different behavior on different PCs (Try 2)

[John DeWeese]

Not much information to go on; maybe you could post the source or 
binary. It's strange that you get exactly 85fps on both systems, given 
such a variance in the hardware. Is your timestep fixed, or are you 
sampling the current time and putting that in? How are you measuring 
fps? Running on windows? What compiler? Do the test_apps work the same 
on both systems?

Looking back in the list archives, it looks like ODE should run 
identically regardless of the platform if it is given an identical 
starting state and step sizes. Someone with more experience should 
chime in as to what conditions would cause different ODE sessions to 
diverge.

   - John

On Friday, April 25, 2003, at 02:41 PM, Frederic Ferland wrote:

> Hi!
>
> I didn't get any reply to my last question, so I'm trying again. :)  
> To summarize my previous post, I'm getting different behavior in my 
> program when I run it on two different computers.  On one, I get the 
> expected behavior and on the other, my objects act like superballs and 
> bounce in the air like crazy when they hit the ground.  Can anyone 
> explain why this might be happening and what can be done about it?  
> How do programs using ODE usually manage to get the same behavior 
> regardless of the speed of the computer being used?
>
> If that can help, you can read my original post in its entirety in the 
> ODE mailing list archive at this address:
> http://q12.org/pipermail/ode/2003-April/008374.html
>
> Thanks for any clue!
>
-------------------
> There's probably a very logical reason for this, but I'm not sure what 
> it
> is.  In the program I wrote, a bunch of cubes and spheres fall in a 
> pile on
> the ground.  If I run the program on my work PC (Pentium 4 @ 1.8Ghz,
> GeForce3 video card), everything works as expected (I developed the 
> program
> on that computer).  However, when I run the same program on my home PC
> (Pentium 3 @ 1.0Ghz, GeForce2 video card), some cubes act like they're
> rubber balls and bounce very high in the sky, while others act weird at
> times (such as being still on the ground for a second or two and then
> bouncing and flipping on another side.)
>
> Can anyone tell me why this is happening?  I thought it might have
> something to do with my frame rate, but I get 85 FPS on both systems.  
> Is
> there something that can be done to prevent this so that I get the same
> behavior on any system, no matter what the system specs are?

>
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