Live for Speed - LFS Main Site
- LFS World
- LFS News
- LFS Manual
- LFS Merchandise
  http://www.setupgrid.net/

Go Back   Live for Speed > Other > Off Topic

Reply
 
Thread Tools Search this Thread Display Modes
Old 2nd October 2008, 12:32   #1  -   
Bob Smith
Moderator
 
Bob Smith's Avatar
 
Join Date: Oct 2003
Location: Sheffield, UK
Posts: 11,230
Bob Smith's online stats
Racing sim physics engine rates

Probably not the best place to post this to get enough attention but this will have to do...

I was wondering, do people know what rates the physics engines of various racing sims run at?

After some research:
'98 Sports Car GT - 50 Hz [from Blackhole Motorsports article]
'98 Viper Racing - 60 Hz (general) / 300 Hz (some aspects) [email with Dave Broske]
'98 Grand Prix Legends - 144 Hz
'00 F1 2000 - 50 Hz [from Blackhole Motorsports article]
'00-'08 Racer - 300 Hz (general) / 3000-30,000 Hz (tyre rotation) [posted by Ruud in a thread archive on racer.nl, dated '01]
'01 F1 2001 - 200 Hz [from Blackhole Motorsports article]
'02 Total Immersion Racing - 100 Hz (uses RK4) [from press release]
'02-'08 Live For Speed - 100 Hz (collision detection) / 2000 Hz (vehicle dynamics) [posted by Scawen on lfsforum]
'03 NASCAR Racing 2003 Season - 288 Hz (possibly)
'04 VirtualRC Racing v1.0 - 300 Hz (general) / 600 Hz (tyre model) [posted by Todd on lfsforum]
'05 VirtualRC Racing v3.0 - 250 Hz (general) / 500 or 1000 Hz (tyre model) [posted by Todd on lfsforum]
'05 rFactor - 400 Hz
'05 Forza Motorsport - 180 Hz
'06 Test Drive Unlimited - 100 Hz (collision detection) / 1000 Hz (vehicle dynamics)
'06 netKar Pro - 333 Hz [posted by Kunos on RSC]
'07 Forza Motorsport 2 - 360 Hz [from wikipedia article]
'07 Rigs Of Rods - 2000 Hz [from ROR forums]
'08 Ferrari Challenge: Trofeo Pirelli - 60 Hz
'08 rFactor Pro - 800 Hz [from official website]
'08 iRacing - 360 Hz [from AutoSimSport]
'09 Supercar Challenge - 60 Hz
'09 Need For Speed: Shift - 180 Hz / might be 360 Hz (effective due to 2 physics passes per timestep?)
'09 Forza Motorsport 3 - 360 Hz [from gamespot article]
Motorsport - 333 Hz (but still being tuned) [posted by Stenyak on RSC]

Anything sim can add to the list, or additional details you could provide, I would be very interested in reading! Cheers.

I've posted this over on RSC too: http://forum.racesimcentral.com/showthread.php?t=329099
__________________
Vehicle Handling and Performance Analyser - In depth setup analysis for LFS and real world vehicles

Last edited by Bob Smith; 26th October 2009 at 22:26. Reason: even more additions
Reply With Quote
Old 2nd October 2008, 13:24   #2  -   
w126
S2 licensed
 
Join Date: Jun 2003
Posts: 186
w126's online stats
netKar PRO - 333 Hz
Source: http://forum.racesimcentral.com/show...50#post3767150

iRacing - 360 Hz
Source: AutoSimSport vol. 4, issue 4, page 28

Last edited by w126; 2nd October 2008 at 13:28.
Reply With Quote
Old 2nd October 2008, 13:32   #3  -   
wsinda
S2 licensed
 
Join Date: Mar 2006
Location: Groningen, NL
Posts: 1,194
wsinda's online stats
Surprisingly, these figures are not present in the Wikipedia comparison. Might be a good idea to add it.
Reply With Quote
Old 2nd October 2008, 13:35   #4  -   
Bob Smith
Moderator
 
Bob Smith's Avatar
 
Join Date: Oct 2003
Location: Sheffield, UK
Posts: 11,230
Bob Smith's online stats
wsinda, that was the first place I checked. I agree it would be handy to see that info in there, although I'm not sure which table would make the best home for this extra column.

Excellent additions, thanks w126, I'll add them to my first post to save people having to read all this thread in the months/years to come.
__________________
Vehicle Handling and Performance Analyser - In depth setup analysis for LFS and real world vehicles
Reply With Quote
Old 2nd October 2008, 13:52   #5  -   
jtw62074
S2 licensed
 
jtw62074's Avatar
 
Join Date: Mar 2004
Posts: 586
jtw62074's online stats
Quote:
Originally Posted by Bob Smith View Post
VirtualRC Racing - 600 Hz, has tested up to 30,000 Hz in the past [posted by Todd on lfsforum, have also read something similar in a usenet posting]
Not sure where the 600Hz came from. It was 300Hz originally and somewhere in the middle I changed it to 250Hz in one of the updates around V2 or V3. The 30,000Hz was only very briefly many years ago (well before Virtual RC Racing was ever released; possibly before I even started work on it) and that was only for the tire model.

Anyway, it's 250Hz now with the tire model running at 1000Hz. Nobody ever noticed the change from 300 to 250, btw.. Up until now I was the only person on the planet that knew

Quote:
Total Immersion Racing - 100 Hz (effectively 400 Hz due to Runge-Kutta 4th order integration rather than Euler?) [from press release]
Don't get too excited about Runge-Kutta solvers. That doesn't make something work like it's 400Hz instead of 100Hz. Just a bunch of marketing BS really...

360Hz is an odd one along with a couple of the others. You could use any frequency you want of course, but if you follow the practice of using milliseconds for timing things then you'll wind up using a multiple of 1/milliseconds. I.e., 1ms = 1000Hz, 2ms = 500Hz, 3ms = 333Hz, 4ms = 250Hz, 5 ms = 200Hz, etc.. That's not a requirement at all, but that's why you'll frequently see these familiar numbers popping up in different sims whether they're racing, flying, boating, first person shooters, and so on.

I thought I'd read way back on rec.autos.simulators that GPL ran at 333Hz. I could be wrong though of course.
__________________
Todd Wasson

Virtual RC Racing Developer
http://www.VirtualRC.com
http://www.PerformanceSimulations.com

Last edited by jtw62074; 2nd October 2008 at 14:01.
Reply With Quote
Old 2nd October 2008, 13:55   #6  -   
AlienT.
S2 licensed
 
AlienT.'s Avatar
 
Racername: RSR.AlienT.
Join Date: Mar 2007
Location: East Lothian, Scot
Posts: 1,181
AlienT.'s online stats
Are these the rates that the physics engine updates? and what difference to the end user, just out of interest. thanks.

What I mean is what the heck are these?
__________________
www.radicalsonline.com
By definition, you have to live until you die. Better to make that life as complete and enjoyable an experience as possible, in case death is shite, which I suspect it will be.
Reply With Quote
Old 2nd October 2008, 14:34   #7  -   
Bob Smith
Moderator
 
Bob Smith's Avatar
 
Join Date: Oct 2003
Location: Sheffield, UK
Posts: 11,230
Bob Smith's online stats
Quote:
Originally Posted by jtw62074 View Post
Not sure where the 600Hz came from.
http://www.lfsforum.net/showthread.p...152#post125152

Quote:
Originally Posted by jtw62074 View Post
Don't get too excited about Runge-Kutta solvers. That doesn't make something work like it's 400Hz instead of 100Hz. Just a bunch of marketing BS really...
I got it from here: http://www.simracingworld.com/content/157/ - the sentence is a little ambiguous to say the least.

Quote:
Originally Posted by jtw62074 View Post
I thought I'd read way back on rec.autos.simulators that GPL ran at 333Hz. I could be wrong though of course.
It's possible. I just had 240 Hz in my head for some reason, although I tried researching it again today and couldn't find where I originally came across the figure.

Thanks for the info though Todd.

Quote:
Originally Posted by AlienT. View Post
Are these the rates that the physics engine updates? and what difference to the end user, just out of interest. thanks.

What I mean is what the heck are these?
Smoother physics, essentially. Less catastrophic collisions with red barrier like objects. Less oscillation problems at low speeds. Less headaches for the programmer(s). More CPU usage.
I've read that simulations used in films often run around 500 Hz, as that's the sweet point to look and act natural.
__________________
Vehicle Handling and Performance Analyser - In depth setup analysis for LFS and real world vehicles
Reply With Quote
Old 2nd October 2008, 14:41   #8  -   
jtw62074
S2 licensed
 
jtw62074's Avatar
 
Join Date: Mar 2004
Posts: 586
jtw62074's online stats
Quote:
Originally Posted by Bob Smith View Post
Oh, right... That 600 was for the tires only when the main engine was at 300 back then. I just checked and currently (I was wrong) the main engine runs at 250Hz with the tires running 500Hz most of the time. At low speed the tires switch to 1000Hz. The RC car tires have almost 0 inertia so you need to run them at a pretty high frequency as you can imagine. The 30,000Hz was overkill. At one point I think I had them running at 60,000Hz. A bit unnecessary

Quote:
Originally Posted by AlienT. View Post
Are these the rates that the physics engine updates? and what difference to the end user, just out of interest. thanks.

What I mean is what the heck are these?
Just like Bob said, it's smoother.

Literally what you're doing in a simulator is calculating the new position, speed, etc., (let's call it the "state") of the car over and over. You can say "the car's speed is now 100 km/h, so where will it be x seconds from now at that speed?"

The "x seconds" is where the frequency comes in. If you calculate the new position/velocity (state) for 1 second from now, the engine is running at 1Hz (cycles per second). That's not very good because nothing you do over the course of an entire second will effect the car at all. The suspension and other forces won't do anything either during that time, so you're better off calculating everything much more often.

In my case on Virtual RC Racing, I say "the car is here now, so let's calculate where it will be 1/250th of a second from now." That's 250Hz. The tire rotational speeds are calculated 2 times during each step, so the frequency there is double: 500Hz.

At some point you don't notice any difference. I can't tell a difference between 250 and 1000 or 10000 Hz in my stuff (I've tried them all), although some people might. Running 1000 versus 250 takes 4 times the processing power though, which means you have that much less available for graphics, sound, AI, etc., so the name of the game is to run as low a frequency as you can get away with while still maintaining good accuracy and response.
__________________
Todd Wasson

Virtual RC Racing Developer
http://www.VirtualRC.com
http://www.PerformanceSimulations.com
Reply With Quote
Old 2nd October 2008, 15:10   #9  -   
AlienT.
S2 licensed
 
AlienT.'s Avatar
 
Racername: RSR.AlienT.
Join Date: Mar 2007
Location: East Lothian, Scot
Posts: 1,181
AlienT.'s online stats
Thanks for the reply....oh and I am going to have a try with VRC it looks very interesting.....you should get together with Bob and give the talented chap a job
__________________
www.radicalsonline.com
By definition, you have to live until you die. Better to make that life as complete and enjoyable an experience as possible, in case death is shite, which I suspect it will be.
Reply With Quote
Old 2nd October 2008, 15:40   #10  -   
blackbird04217
S2 licensed
 
blackbird04217's Avatar
 
Racername: SRS:BlackBird
Join Date: Feb 2007
Location: Maine, US
Posts: 2,102
blackbird04217's online stats
Viper Racing 60hz with some aspects running at 300hz

Source: an e-mail with Dave Broske, on of the programmers on Viper Racing
Reply With Quote
Old 2nd October 2008, 15:41   #11  -   
Bob Smith
Moderator
 
Bob Smith's Avatar
 
Join Date: Oct 2003
Location: Sheffield, UK
Posts: 11,230
Bob Smith's online stats
AlienT. - Since I currently have a job developing driving games (specifically the vehicle dynamics) and am working on two interesting titles atm, I'm in no need of another job.

I brought this thread up since the PC racing sim I'm working on is having low speed issues and I needed to convince my boss that fighting a 60Hz timestep was always going to be a losing battle. I've got it working pretty reasonably, but since we don't need to support the PlayStation 2 anymore, we can afford to use up some more CPU cycles. We're planning to up the core engine to 120Hz and de-couple the drivetrain physics to run even faster, which should make my life much easier, and make for a more credible car simulation.
__________________
Vehicle Handling and Performance Analyser - In depth setup analysis for LFS and real world vehicles
Reply With Quote
Old 2nd October 2008, 15:51   #12  -   
w126
S2 licensed
 
Join Date: Jun 2003
Posts: 186
w126's online stats
Quote:
Originally Posted by jtw62074 View Post
360Hz is an odd one along with a couple of the others.
It has good reason at least in case of Forza Motorsport 2. Their graphics is always at 60 fps (when playing), so with 360 Hz physics rate the graphics is smooth and they don't need to interpolate between 2 physics steps to get the state used for a single graphics frame. LFS also does not have such interpolation but some people notice it's not smooth, for example with 75 Hz monitor refresh rate and full screen vertical sync switched on. (http://www.lfsforum.net/showthread.p...281#post604281)
Reply With Quote
Old 2nd October 2008, 16:34   #13  -   
AlienT.
S2 licensed
 
AlienT.'s Avatar
 
Racername: RSR.AlienT.
Join Date: Mar 2007
Location: East Lothian, Scot
Posts: 1,181
AlienT.'s online stats
Quote:
Originally Posted by Bob Smith View Post
AlienT. - Since I currently have a job developing driving games (specifically the vehicle dynamics) and am working on two interesting titles atm, I'm in no need of another job.
Good on you, It must be nice to do work that you have a genuine interest in.
__________________
www.radicalsonline.com
By definition, you have to live until you die. Better to make that life as complete and enjoyable an experience as possible, in case death is shite, which I suspect it will be.
Reply With Quote
Old 2nd October 2008, 16:48   #14  -   
Bob Smith
Moderator
 
Bob Smith's Avatar
 
Join Date: Oct 2003
Location: Sheffield, UK
Posts: 11,230
Bob Smith's online stats
OK, good progress so far. Anyone have any ideas for: NASCAR series, later ISI engined games (F1 '99-'02, GTR, GT Legends, GTR2, rFactor, RACE), Richard Burns Rally, Grand Prix series, or X Motor Racing?

Quote:
Originally Posted by AlienT. View Post
Good on you, It must be nice to do work that you have a genuine interest in.
Yep, indeed it is. Only downside is that I don't have as much time as I'd like to work on VHPA / my LFS stuff.
__________________
Vehicle Handling and Performance Analyser - In depth setup analysis for LFS and real world vehicles
Reply With Quote
Old 3rd October 2008, 08:56   #15  -   
jtw62074
S2 licensed
 
jtw62074's Avatar
 
Join Date: Mar 2004
Posts: 586
jtw62074's online stats
Quote:
Originally Posted by w126 View Post
It has good reason at least in case of Forza Motorsport 2. Their graphics is always at 60 fps (when playing), so with 360 Hz physics rate the graphics is smooth and they don't need to interpolate between 2 physics steps to get the state used for a single graphics frame. LFS also does not have such interpolation but some people notice it's not smooth, for example with 75 Hz monitor refresh rate and full screen vertical sync switched on. (http://www.lfsforum.net/showthread.p...281#post604281)
Interesting. Didn't know that. Thanks for the info.
__________________
Todd Wasson

Virtual RC Racing Developer
http://www.VirtualRC.com
http://www.PerformanceSimulations.com
Reply With Quote
Old 3rd October 2008, 09:25   #16  -   
Becky Rose
S2 licensed
 
Becky Rose's Avatar
 
Join Date: Mar 2006
Location: Here and There
Posts: 9,650
Becky Rose's online stats
Although the only sim I ever worked on did not get finished and released, I developed a flexible technique for the physics by using a delta. When the car needed extra physics cycles it got them provided the current framerate allowed it.

This allowed me to run physics as low as 1:1 for screen refresh when the car was settled on a straight, and to pile on the calculations in the corners and exits when the car and suspension was working.

Mind you this goes back about 7 or 8 years now and was a much cruder simulation than the games lsited, and the game never got past a few multiplayer alpha demo's with a handful of testers, but conceptually it seemed to work and allowed for much lower CPU loading.

I've never understood the concept of doing things on fixed timings, I do things when they need to be done. It's the same with my multiplayer data packets too. It's a more event driven approach.
Reply With Quote
Old 3rd October 2008, 10:02   #17  -   
Niels Heusinkveld
S2 licensed
 
Niels Heusinkveld's Avatar
 
Join Date: Jun 2005
Posts: 979
Niels Heusinkveld's online stats
GPL for sure , and possibly N2003 run at 288hz (hence the 144fps framerate limit in n2003 (/2) and the 36fps (/8) limit in GPL which might have something to do with it.

I'm quite sure about GPL, and guessing for N4/n2003.

Edit, and F1 2001 had a 'super high rate' option in an INI file somewhere, doubling the frequency from 200 to 400. And, to my knowledge, this is the default for rFactor. (400)

Last edited by Niels Heusinkveld; 3rd October 2008 at 10:06.
Reply With Quote
Old 3rd October 2008, 17:42   #18  -   
Shotglass
S2 licensed
 
Shotglass's Avatar
 
Join Date: May 2005
Posts: 9,948
Shotglass's online stats
Quote:
Originally Posted by Becky Rose View Post
Although the only sim I ever worked on did not get finished and released, I developed a flexible technique for the physics by using a delta. When the car needed extra physics cycles it got them provided the current framerate allowed it.

This allowed me to run physics as low as 1:1 for screen refresh when the car was settled on a straight, and to pile on the calculations in the corners and exits when the car and suspension was working.

Mind you this goes back about 7 or 8 years now and was a much cruder simulation than the games lsited, and the game never got past a few multiplayer alpha demo's with a handful of testers, but conceptually it seemed to work and allowed for much lower CPU loading.

I've never understood the concept of doing things on fixed timings, I do things when they need to be done. It's the same with my multiplayer data packets too. It's a more event driven approach.
afaik the problem with this (apart from whatever nyquist will have to say about bumps) is that online everyone will play with different varying physics
__________________
I think we as a species would be a lot mentally healthier if we stopped taking comfort in delusions and learned to accept the transitive nature of our existence. That's why I spend my Sunday evenings in an airtight box with a poison gas capsule set up to release on the decay of a single radioactive atom.
Reply With Quote
Old 3rd October 2008, 18:54   #19  -   
Bob Smith
Moderator
 
Bob Smith's Avatar
 
Join Date: Oct 2003
Location: Sheffield, UK
Posts: 11,230
Bob Smith's online stats
Deciding what integration frequency is enough is difficult too, as it not only varies with speed, but with the parameters of the car. Low power tanks will likely be fine at 50Hz, RC cars like in Todd's sim need a lot more.

Shotglass - with Becky's exact implementation that is true, but I don't see why varying frequency would cause a problem multiplayer if done carefully. I mean technically speaking Todd is already doing that in VirtualRC.
__________________
Vehicle Handling and Performance Analyser - In depth setup analysis for LFS and real world vehicles
Reply With Quote
Old 3rd October 2008, 19:31   #20  -   
Shotglass
S2 licensed
 
Shotglass's Avatar
 
Join Date: May 2005
Posts: 9,948
Shotglass's online stats
Quote:
Originally Posted by Bob Smith View Post
I mean technically speaking Todd is already doing that in VirtualRC.
is he from how i understand it (tbh im not sure he does himself after correcting the numbers 5 times so far ) all he does is multiply the base rate by some (by what weve read so far most likely random) number to get a higer rate for some subsection of the physics loop

although i do know that all id games up until doom3 used variable physics rates but that was a complete mess
__________________
I think we as a species would be a lot mentally healthier if we stopped taking comfort in delusions and learned to accept the transitive nature of our existence. That's why I spend my Sunday evenings in an airtight box with a poison gas capsule set up to release on the decay of a single radioactive atom.
Reply With Quote
Old 3rd October 2008, 20:11   #21  -   
Becky Rose
S2 licensed
 
Becky Rose's Avatar
 
Join Date: Mar 2006
Location: Here and There
Posts: 9,650
Becky Rose's online stats
Quote:
afaik the problem with this (apart from whatever nyquist will have to say about bumps) is that online everyone will play with different varying physics
Not a problem, my project was written in multiplayer from the start. The trick is careful consideration of the event triggers that scale the physics delta. My game didnt have bumps on the track (we are going back a few years here - we had to keep poly counts down!) but if the track had any noteable bumps i'd set a locational/path trigger in addition to the fall-back of the physics themselves saying "hang on, I need more because thats a big movement". For instance, my physics processed more when near a kerb.

It's often assumed that multiplayer needs to be perfectly synced, in reality it's impossible to perfectly sync anyway because of lag, so you position, rotate and give mommentum according to the remote vehicles data in the packets, but movements of suspension and other fine details are mostly "cosmetic" and also in part to carry on processing movements between updates of the data packet, so really absolute precision of remote vehicles is not necessary. It just has to be "close enough" that corrections in the packet data dont cause visual jitter. I didnt even send data like that in the multiplayer packets (though remember my physics where simpler), if I recall the only "physics" thing sent was once a lap a simple map of tyre wear and fuel load and that was it, other than that it was just position, rotation, and velocity and the physics coped with the rest locally.
Reply With Quote
Old 3rd October 2008, 21:10   #22  -   
Shotglass
S2 licensed
 
Shotglass's Avatar
 
Join Date: May 2005
Posts: 9,948
Shotglass's online stats
the thing with synchonous fixed rate physics is more about having everyone playing the same game
with quake3 for example you can find long articles about why 125fps will let you jump the highest which at the time gave players on high end pcs an advantage and is why doom3 used fixed rate physics
with a sim its obviously even more important
__________________
I think we as a species would be a lot mentally healthier if we stopped taking comfort in delusions and learned to accept the transitive nature of our existence. That's why I spend my Sunday evenings in an airtight box with a poison gas capsule set up to release on the decay of a single radioactive atom.
Reply With Quote
Old 3rd October 2008, 22:09   #23  -   
Juls
S2 licensed
 
Join Date: Jul 2007
Posts: 318
Juls's online stats
Quote:
Originally Posted by Shotglass View Post
the thing with synchonous fixed rate physics is more about having everyone playing the same game
with quake3 for example you can find long articles about why 125fps will let you jump the highest which at the time gave players on high end pcs an advantage and is why doom3 used fixed rate physics
with a sim its obviously even more important
Yes, but this can be avoided if you integrate everything carefuly. Using varying time steps can work...but it introduces many tricky potential bugs, and make things that should be easier like integration between fames become much harder.
It is like using a rotating referential to calculate everything. It works if you think about it all the time.
Reply With Quote
Old 3rd October 2008, 22:23   #24  -   
Becky Rose
S2 licensed
 
Becky Rose's Avatar
 
Join Date: Mar 2006
Location: Here and There
Posts: 9,650
Becky Rose's online stats
aye sounds like shoddy coding to me Shotglass. Or just using a different approach to problems than I do, I do understand what you meen - but I dont see how a sensible approach to the physics cannot treat the physics themselves as a suspension model.

If done right everyone IS playing the same game, you're assuming the physics run at a different rate in the same circumstances whereas this isnt really the case. You set the physics rate based upon the need (and anticipated need) of the calculations it has to do. It's not the same as full 1:1 ratio delta timing, it's using an individual delta for each physics objects and modifying its delta based upon how many calculations it needs to do.

Sure in practice I capped the exponential increase in calculations on framerate on my project, a sensible precaution against slowdown on slow machines, but i'd argue this is prefferable to playing at 15fps.

Think about it logically, does a car travelling down a straight with it's suspension settled need 300 calculations per second? If you can get away with 50 or 10, then why not do that until you get near the corner. Now in a race game most of the time the car is on a straight, so you've just freed up enough CPU cycles to increase the size of the field by 3...

Last edited by Becky Rose; 3rd October 2008 at 22:28.
Reply With Quote
Old 3rd October 2008, 22:40   #25  -   
Shotglass
S2 licensed
 
Shotglass's Avatar
 
Join Date: May 2005
Posts: 9,948
Shotglass's online stats
Quote:
Originally Posted by Juls View Post
It is like using a rotating referential to calculate everything. It works if you think about it all the time.
i guess it can work if done correctly but id rather not think about what it all means in the framework of discrete time maths

Quote:
Originally Posted by Becky Rose View Post
Think about it logically, does a car travelling down a straight with it's suspension settled need 300 calculations per second? If you can get away with 50 or 10, then why not do that until you get near the corner. Now in a race game most of the time the car is on a straight, so you've just freed up enough CPU cycles to increase the size of the field by 3...
it probably doesnt however i dont really see how it might help with framerates when the pc still has to cope with a much higher rate and 3 more cars during the corners where a high framerate is most important
__________________
I think we as a species would be a lot mentally healthier if we stopped taking comfort in delusions and learned to accept the transitive nature of our existence. That's why I spend my Sunday evenings in an airtight box with a poison gas capsule set up to release on the decay of a single radioactive atom.
Reply With Quote
Old 3rd October 2008, 23:03   #26  -   
chavm481
S2 licensed
 
chavm481's Avatar
 
Racername: [SC] Godzilla
Join Date: Jun 2008
Location: In your closet.
Posts: 2,096
chavm481's online stats
whats all this for?
__________________
|ŻŻŻŻŻŻŻŻŻŻ| |ŻŻŻŻŻŻŻŻŻŻ| ___.___ |ŻŻŻ|___\Ż/_,,
|__________| |__________| |______||__________|..
OoŻŻŻŻoo --- OoŻŻŻŻoo --- OoŻŻŻŻoo --- OoŻŻŻŻoo
Reply With Quote
Old 3rd October 2008, 23:44   #27  -   
wheel4hummer
S2 licensed
 
wheel4hummer's Avatar
 
Racername: wheel4hummer
Join Date: Jun 2005
Location: In my pants
Posts: 5,182
wheel4hummer's online stats
Quote:
Originally Posted by chavm481 View Post
whats all this for?
Don't worry about it.
__________________
Quote:
Originally Posted by flymike91 View Post
You're an asshole.
Reply With Quote
Old 4th October 2008, 00:24   #28  -   
chavm481
S2 licensed
 
chavm481's Avatar
 
Racername: [SC] Godzilla
Join Date: Jun 2008
Location: In your closet.
Posts: 2,096
chavm481's online stats
alright.....
__________________
|ŻŻŻŻŻŻŻŻŻŻ| |ŻŻŻŻŻŻŻŻŻŻ| ___.___ |ŻŻŻ|___\Ż/_,,
|__________| |__________| |______||__________|..
OoŻŻŻŻoo --- OoŻŻŻŻoo --- OoŻŻŻŻoo --- OoŻŻŻŻoo
Reply With Quote
Old 4th October 2008, 10:33   #29  -   
Becky Rose
S2 licensed
 
Becky Rose's Avatar
 
Join Date: Mar 2006
Location: Here and There
Posts: 9,650
Becky Rose's online stats
Quote:
it probably doesnt however i dont really see how it might help with framerates when the pc still has to cope with a much higher rate and 3 more cars during the corners where a high framerate is most important
Ah but after T1 field spread ensures that at any given time most cars are on a straight. Watch a big race on LFS Remote, you'll see that after the start at any given time most cars are settled.

The start down to T1 will always be the point of any race game that has the lowest frame rate. There are lots of ways to compensate here by cutting back on eye candy when frame rates are dropping, and in my previous project I chose to make the physics cut back when the framerate dropped below 25, it didnt detriment gameplay - my engine gave me this flexibility, and making the game more responsive more than made up for the lower fidelity physics on the first turn - so it was win-win really.

And like I saw, once the race was settled down I had way more CPU cycles to play with.

To me it makes no sense to do things that are not needed. Games are all about saving CPU cycles and getting the very most out of the performance of the computer, why waste 290 cycles of the physics engine when it doesnt need doing?
Reply With Quote
Old 4th October 2008, 14:46   #30  -   
Shotglass
S2 licensed
 
Shotglass's Avatar
 
Join Date: May 2005
Posts: 9,948
Shotglass's online stats
Quote:
Originally Posted by Becky Rose View Post
Ah but after T1 field spread ensures that at any given time most cars are on a straight.
but once youve got a decent spread physics culling shoud ensure that theres very few cars to calculate anyway

Quote:
To me it makes no sense to do things that are not needed. Games are all about saving CPU cycles and getting the very most out of the performance of the computer, why waste 290 cycles of the physics engine when it doesnt need doing?
i see where youre comming from but i can also understand the advantage of simply using a fixed rate and forget all the worries that a variable one will come back to bite you in the arse at any one point
__________________
I think we as a species would be a lot mentally healthier if we stopped taking comfort in delusions and learned to accept the transitive nature of our existence. That's why I spend my Sunday evenings in an airtight box with a poison gas capsule set up to release on the decay of a single radioactive atom.
Reply With Quote
Reply

  Live for Speed > Other > Off Topic

  • Submit Thread to Digg
  • Submit Thread to del.icio.us
  • Submit Thread to StumbleUpon
  • Submit Thread to Google

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 10:48.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Live for Speed © 2002-2014 - Scawen Roberts, Eric Bailey, Victor van Vlaardingen