Racer v0.39 released

Hi all, Although far from perfect, I've updated Racer on my webpage. http://www.marketgraph.nl/gallery/racer/ Here are some of the new features: - Added info on track timelines used in Racer. - Timelines also really work, so you can now drive an actual lap time! (best lap time is shown under the current lap time) - Physics engine reworked to use quaternions (the car's body now has gyroscopic precession as well). - Gravity now always point down (not that it won't flip! ;-) - views.ini file; it's now possible to create dials, timers etc. in a very flexible way. - Roll centers for the suspensions - Actual camera's from the car.ini file are used (keys 0-9) - Grid/pit positions (easily created from TrackEd too) Known problems: - I've just started using the obese InstallShield. In the quest for speed, no icons will be created yet for the installed programs, so you'll have to add them yourself (to the Start menu), or just run them directly from the installation directory. - Now & then the car starts out shooting for the sky. Pressing Shift-R may help in that case (or restarting). - There are funny things in the track; dips that make it harder to drive. I'll have to test for the closest triangles soon to avoid the 'sinking' of the car. The current future: - Replays; I've got some code in, but it's mostly non-functional yet. - Ghost car; based on the replays ofcourse. - Mouse or keyboard control; to avoid the need for a joystick or wheel. (but it will be crude) As said, there are some problems, so I hope it works ok-ish on most machines. Enjoy the preview! v0.4 will address some of the more buggier points. Ruud van Gaal Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

excellent stuff Ruud ... have to check it out when i get home :). Have you done any work on the body /wheels? It was like a monster truck last time, definitely challenging to drive. ;-) Shane Ruud van Gaal <[email hidden]> wrote in message news:[email hidden]...

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> Hi all, > > Although far from perfect, I've updated Racer on my webpage. > http://www.marketgraph.nl/gallery/racer/ > > Here are some of the new features: > - Added info on track timelines used in Racer. > - Timelines also really work, so you can now drive an actual lap time! > (best lap time is shown under the current lap time) > - Physics engine reworked to use quaternions (the car's body now has > gyroscopic precession as well). > - Gravity now always point down (not that it won't flip! ;-) > - views.ini file; it's now possible to create dials, timers etc. in a > very flexible way. > - Roll centers for the suspensions > - Actual camera's from the car.ini file are used (keys 0-9) > - Grid/pit positions (easily created from TrackEd too) > > Known problems: > - I've just started using the obese InstallShield. In the quest for > speed, no icons will be created yet for the installed programs, so > you'll have to add them yourself (to the Start menu), or just run them > directly from the installation directory. > - Now & then the car starts out shooting for the sky. Pressing Shift-R > may help in that case (or restarting). > - There are funny things in the track; dips that make it harder to > drive. I'll have to test for the closest triangles soon to avoid the > 'sinking' of the car. > > The current future: > - Replays; I've got some code in, but it's mostly non-functional yet. > - Ghost car; based on the replays ofcourse. > - Mouse or keyboard control; to avoid the need for a joystick or > wheel. (but it will be crude) > > As said, there are some problems, so I hope it works ok-ish on most > machines. Enjoy the preview! v0.4 will address some of the more > buggier points. > > Ruud van Gaal > > Ruud van Gaal, GPL Rank +53.25 > Pencil art : http://www.marketgraph.nl/gallery/ > Car simulation: http://www.marketgraph.nl/gallery/racer/

Ruud, I use InnoSetup for my install programs. It's free, really easy to use, and looks professional. http://www.jordanr.cjb.net Thanks for the keyboard input :0) I'll download and try it on my laptop. Hopefully I'll find a way to plug my wheel into the thing ;-) Just curious, how many triangles are in the track you're using? How many in the car? Todd Wasson --- Performance Simulations Drag Racing and Top Speed Prediction Software http://PerformanceSimulations.Com

On Wed, 28 Feb 2001 10:46:57 +1100, "Shane Lowry" <[email hidden]> wrote: >excellent stuff Ruud ... have to check it out when i get home :). Have you >done any work on the body /wheels? It was like a monster truck last time, >definitely challenging to drive. ;-) Yes, hehe, I had that fixed quite quickly, but it was good to see the suspensions in action. :) The wheels now look a lot better. I'll have to export the SCGT models still (need a side texture map, but I believe I have something lying around (from the 3D Studio Max shots)). Seems silly still to need 4 wheel models for left & right & front & back though. But well, would make it even more tasty. The body is the same, except for the physics. I do have an SCGT Mini model here, haha, would be fun (but haven't converted it yet; the physics keep improving so I don't want to modify too many cars). The camera following is awkward though; the pitch following seems reversed, but that's because it's *behind* the car. Need to rethink that again (it was all messed up after the introduction of a quaternion for the body rotation). Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

On 28 Feb 2001 03:09:22 GMT, [email hidden] (J. Todd Wasson) wrote: >Ruud, > > I use InnoSetup for my install programs. It's free, really easy to use, and >looks professional. >http://www.jordanr.cjb.net Thanks! I'll check it out. > Thanks for the keyboard input :0) I'll download and try it on my laptop. >Hopefully I'll find a way to plug my wheel into the thing ;-) You're welcome. :) But the keyboard input isn't yet in this version (although on the SGI I *only* use the mouse & keyboard, so it shouldn't be that hard). > Just curious, how many triangles are in the track you're using? How many in >the car? Good question. Hm, the car has got perhaps 300 triangles or so. The track is far more, but is being culled away (details on my site in the programmer's section) quite effectively. I have a Monza track lying around, which looks a lot better (it's from F12K), but took up a lot of texture memory. Haven't played with that since optimizing texture use though. I think there are about 100 triangles or so per track object, and about 90 or so of those. So only 9000, and then some trucks, grandstands and such. I really can't tell for sure. Might be a nice statistical thing. It runs at 40 to 60fps on my PII-400/TNT2Ultra (sadly at only 13fps on the SGI). BTW I can recommend the G. Genta book very much; a lot of direct formulas and numbers. And 5 complete Pacejka samples for different vehicles. Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

I tried running it last night and ended up with a bouncing car. Hmmm looked like the car started just above the track and the rebound of the supsension produced a greater force. The end result was two bounces and then through the roof. Is the start point soft set in one of the ini files Ruud ? rgds Shane Ruud van Gaal <[email hidden]> wrote in message news:[email hidden]... > On Wed, 28 Feb 2001 10:46:57 +1100, "Shane Lowry" > <[email hidden]> wrote: > > >excellent stuff Ruud ... have to check it out when i get home :). Haveyou

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> >done any work on the body /wheels? It was like a monster truck last time, > >definitely challenging to drive. ;-) > > Yes, hehe, I had that fixed quite quickly, but it was good to see the > suspensions in action. :) > The wheels now look a lot better. I'll have to export the SCGT models > still (need a side texture map, but I believe I have something lying > around (from the 3D Studio Max shots)). Seems silly still to need 4 > wheel models for left & right & front & back though. But well, would > make it even more tasty. > The body is the same, except for the physics. I do have an SCGT Mini > model here, haha, would be fun (but haven't converted it yet; the > physics keep improving so I don't want to modify too many cars). > The camera following is awkward though; the pitch following seems > reversed, but that's because it's *behind* the car. Need to rethink > that again (it was all messed up after the introduction of a > quaternion for the body rotation). > > > Ruud van Gaal, GPL Rank +53.25 > Pencil art : http://www.marketgraph.nl/gallery/ > Car simulation: http://www.marketgraph.nl/gallery/racer/

"Shane Lowry" <[email hidden]> schrieb im Newsbeitrag news:97jp5m$i4q$[email hidden]... Hi! > I tried running it last night and ended up with a bouncing car. Hmmmlooked > like the car started just above the track and the rebound of thesupsension > produced a greater force. The end result was two bounces and then through > the roof. Is the start point soft set in one of the ini files Ruud ? Same here. I edited the section in the "car.ini" that says: ; Location; give it a bit of height for the wheels hanging on ; it will fall down to the ground by itself x=0 y=0.35 z=0 to ; Location; give it a bit of height for the wheels hanging on ; it will fall down to the ground by itself x=0 y=0 z=0 but to no avail. Something f***s up there ;)). Regards Crash

Hi! Same here. I edited the section in the "car.ini" that says: ; Location; give it a bit of height for the wheels*** on ; it will fall down to the ground by itself x=0 y=0.35 z=0 to ; Location; give it a bit of height for the wheels*** on ; it will fall down to the ground by itself x=0 y=0 z=0 but to no avail. Something f***s up there ;)). Regards Crash

I heard that GPL had the same problem during development and the 288Hz physics model was chosen because it alleviated the problem. "Shane Lowry" <[email hidden]> wrote in message news:97jp5m$i4q$[email hidden]... > I tried running it last night and ended up with a bouncing car. Hmmmlooked > like the car started just above the track and the rebound of thesupsension > produced a greater force

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>> Thanks for the keyboard input :0) I'll download and try it on my laptop. >>Hopefully I'll find a way to plug my wheel into the thing ;-) > >You're welcome. :) But the keyboard input isn't yet in this version >(although on the SGI I *only* use the mouse & keyboard, so it >shouldn't be that hard). >

Cool. I downloaded Racer, but haven't tried it yet. Got sidetracked working last night, you know how it goes :-) That's a lot of triangles (to me, at least!) I was curious how many ground triangle intersection checks you needed to make each loop and how you were handling that. Without a really good search pattern, that many triangles would slow my engine to a crawl. >BTW I can recommend the G. Genta book very much; a lot of direct >formulas and numbers. And 5 complete Pacejka samples for different >vehicles. Great, thanks! I've gotta move in about three weeks, so it'll have to wait yet. I think I'm dumping Pacejka's methods for now and trying a brush based model instead. An experiment based on this type of model worked well, but I've only handled the lateral direction so far. It did a good job of predicting how peak slip angle at max force changes with tire load, and the curve shape varied pretty well with variations in static and dynamic friction settings. Anyway, that's where I'm at. BTW, I figured out how to model several different differentials, but I ain't tellin' yet! Muuuhahaha!! <Evil grin> I'll still have to check out Genta's book. Thanks for the tip! Todd Wasson --- Performance Simulations Drag Racing and Top Speed Prediction Software http://PerformanceSimulations.Com

On Wed, 28 Feb 2001 23:48:08 +0100, "Joachim Blum" <[email hidden]> wrote:

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>"Shane Lowry" <[email hidden]> schrieb im Newsbeitrag >news:97jp5m$i4q$[email hidden]... > >Hi! > >> I tried running it last night and ended up with a bouncing car. Hmmm >looked >> like the car started just above the track and the rebound of the >supsension >> produced a greater force.

Yes, that's a problem. Some suggestions: - in debug.ini, set the integration time to 1 (it defaults to 4, meaning 250Hz). That will get you 1000Hz. - in the car.ini (data/ferp4/car.ini), try reducing wheel*.tire_rate. I have a hunch that this is a number that is giving me some trouble in the bouncing area (it produces high forces/frequencies very fast). Note that I sometimes see the first frame with a car point the wrong direction. The next frame, I see the car in the warped direction at grid position 0, as it should be. Perhaps this first weird frame is the cause (perhaps draw_every_step=1 will reveal the bug every time). The suspensions are sensitive to wheel motion and might get kicked because of this bad frame (at which perhaps the car is *IN* the tarmac, producing a huge force). > The end result was two bounces and then through >> the roof. Remind me to build a moon so you can try to target it. ;-) (and ofcourse, drive on there!) > Is the start point soft set in one of the ini files Ruud ? It's done from TrackEd; the first grid position. As it raytraces into the track, you can't really set a height. Ehm, ofcourse you can! In data/tracks/special.ini you'll find the grid positions, including Y values. You *might* want to try heightening them, but a falling car quickly goes into a bounce. Also, try to do a Shift-R real fast to get a softer landing. However, sometimes after some racing the suspension motion keeps going, even when not driving. >Same here. I edited the section in the "car.ini" that says:... > ; Location; give it a bit of height for the wheels hanging on > ; it will fall down to the ground by itself > x=0 > y=0 > z=0 This isn't used anymore; I'll have to throw it out. It was there to keep the body from starting in the road. Now, the grid position is used, and a *magic* value is used to lift the car somewhat to allow for the wheels to just not touch the ground. This magic value is set at 0.5 currently and not editable through an ini file. Because it should be calculated by looking at the suspension rest length and the radius of the wheel. Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

On Wed, 28 Feb 2001 14:51:06 -0800, "Kirk House" <[email hidden]> wrote: >I heard that GPL had the same problem during development and the 288Hz >physics model was chosen because it alleviated the problem. The question is; what did they use before that? Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

On 01 Mar 2001 09:26:38 GMT, [email hidden] (J. Todd Wasson) wrote: ... > Cool. I downloaded Racer, but haven't tried it yet. Got sidetracked working >last night, you know how it goes :-) Yes, I'm at a deadline for Saturday for a new project too. It's hard to get some REAL work done! ;-) > That's a lot of triangles (to me, at least!) I was curious how many ground >triangle intersection checks you needed to make each loop and how you were >handling that. Without a really good search pattern, that many triangles would >slow my engine to a crawl. The track is divided into a number of geometrical objects. The DOF files that are in data/tracks/oval1. For each of those, I keep a bounding sphere. Then when looking for triangles, I walk the list of all DOFs and see if the car's inside the bounding sphere. If so, I walk every triangle and see if it hits. So I test perhaps an average of 30 triangles PER wheel PER iteration. So that's still a lot of work, and can use some optimization. Especially if the track is not divided a lot, or the bounding spheres do not represent the object very good, the miss-hits can become quite large and press down on the fps.

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> >BTW I can recommend the G. Genta book very much; a lot of direct >>formulas and numbers. And 5 complete Pacejka samples for different >>vehicles. > > Great, thanks! I've gotta move in about three weeks, so it'll have to wait >yet. I think I'm dumping Pacejka's methods for now and trying a brush based >model instead.

Where did you get info on the brush model? > An experiment based on this type of model worked well, but I've >only handled the lateral direction so far. It did a good job of predicting how >peak slip angle at max force changes with tire load, and the curve shape varied >pretty well with variations in static and dynamic friction settings. Anyway, >that's where I'm at. Sounds like it's going nicely. :) > BTW, I figured out how to model several different >differentials, but I ain't tellin' yet! Muuuhahaha!! <Evil grin> Damn! Lol, I'm not into differentials yet, but well, I'll ask you one day when you had too much to drink then. ;-) Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

Hi Ruud Dont forget to cache the last poly hit for ech wheel and make that the first poly you check next time. Tell me to shut up if you already do that :O) Chris Ruud van Gaal <[email hidden]> wrote in message news:[email hidden]... > On 01 Mar 2001 09:26:38 GMT, [email hidden] (J. Todd Wasson) wrote: > > ... > > Cool. I downloaded Racer, but haven't tried it yet. Got sidetrackedworking > >last night, you know how it goes :-) > > Yes, I'm at a deadline for Saturday for a new project too. It's hard > to get some REAL work done! ;-) > > > That's a lot of triangles (to me, at least!) I was curious how manyground > >triangle intersection checks you needed to make each loop and how youwere > >handling that. Without a really good search pattern, that many triangleswould

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> >slow my engine to a crawl. > > The track is divided into a number of geometrical objects. The DOF > files that are in data/tracks/oval1. For each of those, I keep a > bounding sphere. Then when looking for triangles, I walk the list of > all DOFs and see if the car's inside the bounding sphere. If so, I > walk every triangle and see if it hits. > So I test perhaps an average of 30 triangles PER wheel PER iteration. > So that's still a lot of work, and can use some optimization. > Especially if the track is not divided a lot, or the bounding spheres > do not represent the object very good, the miss-hits can become quite > large and press down on the fps. > > > >BTW I can recommend the G. Genta book very much; a lot of direct > >>formulas and numbers. And 5 complete Pacejka samples for different > >>vehicles. > > > > Great, thanks! I've gotta move in about three weeks, so it'll have to

wait > >yet. I think I'm dumping Pacejka's methods for now and trying a brushbased > >model instead. > > Where did you get info on the brush model? > > > An experiment based on this type of model worked well, but I've > >only handled the lateral direction so far. It did a good job ofpredicting how > >peak slip angle at max force changes with tire load, and the curve shapevaried > >pretty well with variations in static and dynamic friction settings.Anyway,

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> >that's where I'm at. > > Sounds like it's going nicely. :) > > > BTW, I figured out how to model several different > >differentials, but I ain't tellin' yet! Muuuhahaha!! <Evil grin> > > Damn! Lol, I'm not into differentials yet, but well, I'll ask you one > day when you had too much to drink then. ;-) > > > Ruud van Gaal, GPL Rank +53.25 > Pencil art : http://www.marketgraph.nl/gallery/ > Car simulation: http://www.marketgraph.nl/gallery/racer/

On Thu, 1 Mar 2001 16:42:38 -0000, "Chris West" <[email hidden]> wrote: >Hi Ruud > >Dont forget to cache the last poly hit for ech wheel and make that the first >poly you check next time. Tell me to shut up if you already do that :O) Ouch, ehm, do carry on Chris. ;-) But, caching is indeed high on the optimization list. It's just that it's still doing so nicely that I instead wandered out to other new features. But indeed, just caching the poly, and one step behind that, caching the last found bounding sphere, can and *will* increase speed a LOT. :) Anxious to build it in actually, and see what it does at that track I had yesterday (I noticed that not the graphics, not the physics, but the triangle hits meant everything to the FPS). Now where was that stack of tasklists... Oh gosh, at home. :( Thanks for the re-enlightenment though! Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

>Then when looking for triangles, I walk the list of >all DOFs and see if the car's inside the bounding sphere. If so, I >walk every triangle and see if it hits. >So I test perhaps an average of 30 triangles PER wheel PER iteration. Oh, ok. I'm not that far yet. Right now, I limit my tracks to about 4-600 ground triangles. Haven't implemented Chris' suggestion yet as far as caching triangles. You're right, this would dramatically increase speed. I'll eventually (by the year 3000 or so) check the first wheel's intersection, then start the other three wheels intersection checks with that triangle, since they usually hit the same one anyway. Then, on the next loop, start with the same triangle they hit last step. This would boost speed probably 10-50+ times :-) Hopefully my brain won't catch on fire this time.... >Where did you get info on the brush model? The idea came from looking at the diagrams shown all over the web and in texts like Doug Milliken's awesome book, "Race Car Vehicle Dynamics." Look on page 23. I took the contact patch and split it into 100 or so sections that stretch from left to right across the tread, then let all the sections behave like springs. It works pretty well, but it's probably too intensive to do it real time, although that would probably be the ultimate tire model :-) To find pneumatic trail and tire aligning torque, all I need to do is find the force centroid and take the distance from there to the patch center. (Haven't done it yet) I'll get to the longitudinal aspect before too long. Combining them shouldn't be too tough (yeah, right!) Either way, I think I'll end up with a massive array of data that's pretty good. The cool thing is, by changing the lateral, longitudinal, and vertical spring rates of the sections, the data could change with air pressure variations and give realistic results. I don't think I can predict load sensitivity, since I don't know what causes it (I have an idea, but that would be really complicated to model) , but it can easily be input directly into the code anyway. I also believe that the amount of sliding in each section could give basic tire heating info, but I'm not that far yet :-) I'm gonna stay home tonight and see if I can get the new driveline model with an open differential running. It works on paper so far, but....who knows?? lol You know how it goes :0) If this works, I think I could split each section (strips that go from the left to right side of the contact patch) into several sections themselves (in the lateral direction). This way, camber angle would effect localized load across the tread width and effect lateral and longitudinal force and tire aligning torque. What I will really need then is a way to reverse engineer Pacejka's formula to get coefficients to match the "test" data, and run that through the sim the same way you and almost everybody else probably do it. I have no clue how tire engineers derive the coefficients from real test data, but that's what I'd need to do then. Maybe an iterative approach could work. This could be kind of a "poor man's" numerical analysis tool for tires that could be designed by a player. Who knows? It just might work :0) Todd Wasson --- Performance Simulations Drag Racing and Top Speed Prediction Software http://PerformanceSimulations.Com

Btw, any particulare reason why the DOF-file s takes ages to install... (in particulare Sidb19.dof)? Sidb19.dof is a 5kb file... but yet if I tyr and open it in - say notepad... it will make my system slooooooooooooowwwwwwwwwwwww down... It even take ages to virus scan some if these files.... Me thinks something is wrong... ed_

Sometime ago I wrote: > Btw, any particulare reason why the DOF-file s takes ages to install...(in > particulare Sidb19.dof)? > > Sidb19.dof is a 5kb file... but yet if I tyr and open it in - say > notepad... it will make my system slooooooooooooowwwwwwwwwwwww down... Make that Sidb18.dof btw... Something if clearly wrong here... it took me 10mins to install version 0391! (i.e the damn computer used 8+ minutes to install a single 5kb file!! - and 2 mins on the rest of them.. Just loading racer takes ages too... - 5-10 mins to be exact. What gives? ed_ OH! Just incase... this on a Win98SE, Celly 700, 128mb Pc-100 Ram, V4500, DX7.0a system...

On 03 Mar 2001 03:37:55 GMT, [email hidden] (J. Todd Wasson) wrote: ...

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> Oh, ok. I'm not that far yet. Right now, I limit my tracks to about 4-600 >ground triangles. Haven't implemented Chris' suggestion yet as far as caching >triangles. You're right, this would dramatically increase speed. I'll >eventually (by the year 3000 or so) check the first wheel's intersection, then >start the other three wheels intersection checks with that triangle, since they >usually hit the same one anyway. Then, on the next loop, start with the same >triangle they hit last step. This would boost speed probably 10-50+ times :-)

I'd say a lot more even, since with the relatively small time steps, the chances that your triangle will hit are huge. I'd say the impact of 4-600 triangle would be more in the hundreds. :) Now physics will be even faster. >>Where did you get info on the brush model? > > The idea came from looking at the diagrams shown all over the web and in >texts like Doug Milliken's awesome book, "Race Car Vehicle Dynamics." Look on >page 23. I'll have a look. First I'll have to view the Australian GP. Just got back from work, and gosh, I need some time off, to explore some new ideas for the suspension which is bugging me. > I took the contact patch and split it into 100 or so sections... > What I will really need then is a way to reverse engineer Pacejka's formula Sounds good. I hope though somehow getting Pacejka data will be more easy in the future, since seemingly more people are using it. WSC is, for example. It's just the numbers to plug in are hard to find (which you know ofcourse, since you're trying to get at Pacejka numbers in another way). Sounds like a nice model, although very intensive. Good luck with anyway! Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

On Sat, 3 Mar 2001 07:29:36 +0100, "Ed Solheim" <[email hidden]> wrote:

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>Sometime ago I wrote: > >> Btw, any particulare reason why the DOF-file s takes ages to install... >(in >> particulare Sidb19.dof)? >> >> Sidb19.dof is a 5kb file... but yet if I tyr and open it in - say >> notepad... it will make my system slooooooooooooowwwwwwwwwwwww down... > >Make that Sidb18.dof btw...

Ed, it's strange, I have no problem opening either files. Takes about 0.1 second, if my eye blinking didn't mangle that number. If *notepad* can't open the file (it's a binary btw), try something like a hexdumper, but I really think that this is some problem with your OS or harddisk or something, since I can't really help it if notepad takes 5 minutes to open a 1 sector-sized file. >Something if clearly wrong here... it took me 10mins to install version >0391! (i.e the damn computer used 8+ minutes to install a single 5kb >file!! - and 2 mins on the rest of them.. > >Just loading racer takes ages too... - 5-10 mins to be exact. Must be the loading of the same file. For me, on PII400, 256Mb TNT2U32Mb, loading Racer takes about 10 seconds or so. Installing it takes even less. Have you tried to install it on another partition or harddisk? (or even OS?) Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

>I'd say a lot more even, since with the relatively small time steps, >the chances that your triangle will hit are huge. I'd say the impact >of 4-600 triangle would be more in the hundreds. :) >Now physics will be even faster. > > Yes, you're probably right. Maybe real-time brush tire modelling IS possible :0)!! I'll have to play with that one. >Just got >back from work, and gosh, I need some time off, to explore some new >ideas for the suspension which is bugging me. Sounds good. Are you going to try the A-arm kinematics? Ask Chris about it, he'll probably help.

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>Sounds good. I hope though somehow getting Pacejka data will be more >easy in the future, since seemingly more people are using it. WSC is, >for example. It's just the numbers to plug in are hard to find (which >you know ofcourse, since you're trying to get at Pacejka numbers in >another way). >Sounds like a nice model, although very intensive. Good luck with >anyway! > >

Thanks :0) Todd Wasson --- Performance Simulations Drag Racing and Top Speed Prediction Software http://PerformanceSimulations.Com

On 06 Mar 2001 00:34:12 GMT, [email hidden] (J. Todd Wasson) wrote: ... > Yes, you're probably right. Maybe real-time brush tire modelling IS possible >:0)!! I'll have to play with that one. Perhaps if you can reduce the patch subdivision in real time, based on how much things vary across the tire, you can have a good improvement. Other than that, I'm going the Pacejka route. > Sounds good. Are you going to try the A-arm kinematics? Ask Chris about it, >he'll probably help. He's given me a little hint about suspensions. About energy conservation. I'm going to try that real soon. I'd say a spring with wheel movement should contain it's energy level. Although I should not take into that the movement of the wheel in world space; just relative to the suspension. The funny thing though is where to leave the energy burned as heat in the damper. That would seem to make the energy level go down. Which also means that when hitting a bump, the energy level in the spring/wheel combination would go up, or not hmm. I'll go investigate this with some new set of view elements which can visually display some parameters 'live'. Will be cool. Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

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>He's given me a little hint about suspensions. About energy >conservation. I'm going to try that real soon. I'd say a spring with >wheel movement should contain it's energy level. Although I should not >take into that the movement of the wheel in world space; just relative >to the suspension. The funny thing though is where to leave the energy >burned as heat in the damper. That would seem to make the energy level >go down. >Which also means that when hitting a bump, the energy level in the >spring/wheel combination would go up, or not hmm. I'll go investigate >this with some new set of view elements which can visually display >some parameters 'live'. Will be cool.

Interesting. I've got no idea where or why energy should be calculated. Todd Wasson --- Performance Simulations Drag Racing and Top Speed Prediction Software http://PerformanceSimulations.Com

On 08 Mar 2001 22:37:25 GMT, [email hidden] (J. Todd Wasson) wrote:

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>>He's given me a little hint about suspensions. About energy >>conservation. I'm going to try that real soon. I'd say a spring with >>wheel movement should contain it's energy level. Although I should not >>take into that the movement of the wheel in world space; just relative >>to the suspension. The funny thing though is where to leave the energy >>burned as heat in the damper. That would seem to make the energy level >>go down. >>Which also means that when hitting a bump, the energy level in the >>spring/wheel combination would go up, or not hmm. I'll go investigate >>this with some new set of view elements which can visually display >>some parameters 'live'. Will be cool. > > Interesting. I've got no idea where or why energy should be calculated.

It seems at least one of the reasons why WSC can run so low as 100Hz. Normally, you'll have trouble with the high frequencies that tire rates (and F1 spring rates as well) generate. In other words, your Euler integration steps create errors that are too big. Somehow, by calculating the energy in the system, you can restrict the steps/errors so the energy involved in the wheel moving (relative to the suspension, I guess) and the stored energy in the spring itself, doesn't grow so that energy seems to be put in out of nothing. This limiting of energy growth seems a nice thing to look into. If it can prevent 'over-bouncing' the wheels, it would make things just a bit smoother (and at a smaller integration step). I believe this will be necessary for it to get as low as 100Hz. But the thing I don't get is this; dampers reduce the energy in the wheel/spring combination, because it disappates (sp?) energy into heat (into its oil). So energy *can* disappear. Now when you hit a bump and things start moving, energy *must* be put in somewhere. Not quite figured out how this should work yet. Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

Ruud van Gaal wrote:

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> > This limiting of energy growth seems a nice thing to look into. If it > can prevent 'over-bouncing' the wheels, it would make things just a > bit smoother (and at a smaller integration step). I believe this will > be necessary for it to get as low as 100Hz. > But the thing I don't get is this; dampers reduce the energy in the > wheel/spring combination, because it disappates (sp?) energy into heat > (into its oil). So energy *can* disappear. Now when you hit a bump and > things start moving, energy *must* be put in somewhere. > Not quite figured out how this should work yet. > > Ruud van Gaal, GPL Rank +53.25 > Pencil art : http://www.marketgraph.nl/gallery/ > Car simulation: http://www.marketgraph.nl/gallery/racer/

Hi Ruud, Take the dampers away, and ideally the whole car-wheels-springs system should conserve energy when not in contact with the ground. The damper are indeed a source of disippation, and the energy should decrease, that's what they're there for :). I don't think conservation of energy per se can be easily included into numerical calculations; however, checking for unexpected too large growths in energy might help with some instabilities that occur in numerical integration, as this is usually a clear intication that the timestep is too large. If you are really striving to keep the timestep over or at about 1/100 s, I think it's hard if you want to treat wheels as an inertial object with regard to suspension travel. A timestep of 1/100s allows the frequencies of the order of 100Hz to be modelled at best regardless of the numerical method used. Based on an estimate from the Millikens' book, this coincides about the characteristic time that is present for the wheels of a Champ Car taking into account the tire spring rate. While this indicates that the calculations may work while the car is firmly on the ground, any jumps and subsequent contacts will most likely create instabilities. -Gregor

>It seems at least one of the reasons why WSC can run so low as 100Hz. >Normally, you'll have trouble with the high frequencies that tire >rates (and F1 spring rates as well) generate. >In other words, your Euler integration steps create errors that are >too big. My biggest problem was in the rotational stability of the tires, so I run that part on its on high frequency loop inside the main loop. I suppose the suspension and all the other parts could be done the same way, with their own frequencies. Still, I'm sure Chris' methods are quite a bit more advanced and efficient than mine. I'm not much of a mathematician :0) > Somehow, by calculating the energy in the system, you can >restrict the steps/errors so the energy involved in the wheel moving >(relative to the suspension, I guess) and the stored energy in the >spring itself, doesn't grow so that energy seems to be put in out of >nothing. >This limiting of energy growth seems a nice thing to look into. Interesting. I wouldn't have thought of that in a million years. Let me know how it goes, I have no idea how this would work.

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>This limiting of energy growth seems a nice thing to look into. If it >can prevent 'over-bouncing' the wheels, it would make things just a >bit smoother (and at a smaller integration step). I believe this will >be necessary for it to get as low as 100Hz. >But the thing I don't get is this; dampers reduce the energy in the >wheel/spring combination, because it disappates (sp?) energy into heat >(into its oil). So energy *can* disappear. Now when you hit a bump and >things start moving, energy *must* be put in somewhere. >Not quite figured out how this should work yet. >

So you'd basically do some sort of energy check and limit wheel movement based on this? I'm completely lost! lol Todd Wasson --- Performance Simulations Drag Racing and Top Speed Prediction Software http://PerformanceSimulations.Com

> A timestep of 1/100s allows the >frequencies of the order of 100Hz to be modelled at best regardless of >the numerical method used. Based on an estimate from the Millikens' >book, this coincides about the characteristic time that is present for >the wheels of a Champ Car taking into account the tire spring rate. With a suspension frequency of 100Hz, I'd say he'd need a lot finer resolution than 1/100s time step. I tried the Champ Car data from Millikens' book in my model. With 300Hz sampling rate, it worked fine as long as the wheels stayed on the ground and didn't change surface slopes too abruptly. Dropping the car from a meter or so caused some pretty serious bouncing, as you predicted. It took fairly heavy damping to control. Todd Wasson --- Performance Simulations Drag Racing and Top Speed Prediction Software http://PerformanceSimulations.Com

On 10 Mar 2001 05:49:25 GMT, [email hidden] (J. Todd Wasson) wrote: ... > My biggest problem was in the rotational stability of the tires, so I run >that part on its on high frequency loop inside the main loop. Ah, interesting. Ofcourse, that can be done, not even too difficult. > I suppose the >suspension and all the other parts could be done the same way, with their own >frequencies. Still, I'm sure Chris' methods are quite a bit more advanced and >efficient than mine. I'm not much of a mathematician :0) Yep, well, in the end a lot of it comes from just growing the physics model, I've noticed. You can add more and more stuff, and get a lot of functionality in the beginning, but new parts will enhance the feeling. It's great. Just did Pacejka modeling yesterday night btw. Phew, it worked after just 3 hours! :)) It's just strange to use it as a braking curve as well. That doesn't seem right. ... > Interesting. I wouldn't have thought of that in a million years. Let me >know how it goes, I have no idea how this would work. It would involve detecting strange changes in energy. Note that a lot of apps do this 'type' of programming. Excel for example was/is debugged using multiple different algorithms to do the same thing. 1 is the smart way, the other (non-release) is the slow but robust way. If the 2 algo's disagree, you can print a message. The rigid body classes from Chaney also has an Energy() function. It's meant as a test; the total energy of the car while flipping and flying in the air should remain constant. If not, you know there's some funny business. It's hooking in another approach which should match. ... > So you'd basically do some sort of energy check and limit wheel movement >based on this? I'm completely lost! lol Yep, limit velocity rather than movement. So 1/2mv^2 + potential energy (mg) (relative to the suspension) remains equal. Ah well, it's running ok now at 250Hz, but there's a big problem ahead. Now that I have Pacejka running I have aligning moment and can have some fun trying force feedback, the biggest problem is the geometry of the track. I have a small (Carrera) track which I want to release, but the polygon subdivision is too small, so you get real bumps as opposed to smoothly varying gradients. The same is true for the Oval, although it is a bit better there. So I'll have to do splines to define the road surface, and create a patch surface from the road. Thinking about Hermite splines to start with, but will have to dive into patch/ray intersections soon. WSC does multiple spline types, ofcourse. ;-) Wonder how it does bumps, like the famous bump in Monaco. That's currently the biggest thing I see in finally getting acceptable laptimes on the tracks. But it's a big challenge, all those splines. A lot of work for the track editor. Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

Cool! I just went to your site and checked this out, but was surprised that keyboard (arrow keys) support is not in the sim.. Is this a typo on the requirements page, or am I out of luck? Thanks! On Tue, 27 Feb 2001 23:01:18 GMT, [email hidden] (Ruud van Gaal) wrote: >Hi all, > >Although far from perfect, I've updated Racer on my webpage. >http://www.marketgraph.nl/gallery/racer/ -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 80,000 Newsgroups - 16 Different Servers! =-----

On Wed, 14 Mar 2001 20:35:22 -0500, hobbit <nospam@here> wrote: >Cool! I just went to your site and checked this out, but was surprised >that keyboard (arrow keys) support is not in the sim.. Is this a typo >on the requirements page, or am I out of luck? You're halfly out of luck. No real keyboard is supported, and will never be completely actually, since keyboard controls are a bit too digital to drive a simulation like this (step on the throttle/no throttle is not the way to get good laptimes :). However, I'm doing mouse support, so I hope to have a mouse control set ready for v0.4, so you can play around and then hopefully get a joystick or wheel for the real action. ;-) Oh, make that with force feedback. :)

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>Thanks! > >On Tue, 27 Feb 2001 23:01:18 GMT, [email hidden] (Ruud van Gaal) >wrote: > >>Hi all, >> >>Although far from perfect, I've updated Racer on my webpage. >>http://www.marketgraph.nl/gallery/racer/

Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/

Thanks! Actually, I have 3 wheels, 2 sets of pedals, and 4 different sticks and dislike most all of them.. To each their own, I guess! On Thu, 15 Mar 2001 12:22:14 GMT, [email hidden] (Ruud van Gaal) wrote:

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>On Wed, 14 Mar 2001 20:35:22 -0500, hobbit <nospam@here> wrote: > >>Cool! I just went to your site and checked this out, but was surprised >>that keyboard (arrow keys) support is not in the sim.. Is this a typo >>on the requirements page, or am I out of luck? > >You're halfly out of luck. No real keyboard is supported, and will >never be completely actually, since keyboard controls are a bit too >digital to drive a simulation like this (step on the throttle/no >throttle is not the way to get good laptimes :). >However, I'm doing mouse support, so I hope to have a mouse control >set ready for v0.4, so you can play around and then hopefully get a >joystick or wheel for the real action. ;-) Oh, make that with force >feedback. :) > >>Thanks! >> >>On Tue, 27 Feb 2001 23:01:18 GMT, [email hidden] (Ruud van Gaal) >>wrote: >> >>>Hi all, >>> >>>Although far from perfect, I've updated Racer on my webpage. >>>http://www.marketgraph.nl/gallery/racer/ > >Ruud van Gaal, GPL Rank +53.25 >Pencil art : http://www.marketgraph.nl/gallery/ >Car simulation: http://www.marketgraph.nl/gallery/racer/

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On Thu, 15 Mar 2001 22:02:07 -0500, hobbit <[email hidden]> wrote: >Thanks! Actually, I have 3 wheels, 2 sets of pedals, and 4 different >sticks and dislike most all of them.. To each their own, I guess! Keep 'em. I'm building in analog clutch support, so you might want to test that, if only for fun. :) Ruud van Gaal, GPL Rank +53.25 Pencil art : http://www.marketgraph.nl/gallery/ Car simulation: http://www.marketgraph.nl/gallery/racer/