rec.autos.simulators

Sirocco Racing : New Sim Demo

Ashley McConnel

Sirocco Racing : New Sim Demo

by Ashley McConnel » Tue, 25 Mar 2003 23:33:41

Hi Folks,

As it seems to be a slow news day in RAS-land I thought i'd spam my new demo
:)

**Note - The collision detection code isnt finished, so only the tyres
collide with the surface.  This causes problems with walls / trees as the
tyre thinks it has been compressed by ~1000mm and so rebounds madly ;).
Shift-R quickly i'd suggest :).**

http://www.racesimcentral.net/

Here are the improvements since the last version: -

a.. Multiplayer - the start of a Client-Server based multiplayer system
a.. Multiplayer Chat
a.. Force Feedback - based around lateral tyre force
a.. New Car - the JTCC NSX modelled superbly by CD_QuikSilver
a.. Differential - basic adjustable viscous diff added
a.. Engine Braking - adjusted to be dependent on engine speed
a.. Problem fixed - error when calculating the speed of the engine
a.. Problem fixed - tyre forces being applied in slightly the wrong
direction

If you call into VROC i'll turn on the multiplayer server.  It currently
automatically tries to connect to the server, if you want to stop this set
"startasclient" in ./data/options.ini to 0.  You can also create your own
server by changing startasserver to 1 in options.ini.  I will upload the
dedicated server to the downloads section in a couple of hours.

Have fun :)

All the best,
Ash
http://www.racesimcentral.net/

Ruud van Ga

Sirocco Racing : New Sim Demo

by Ruud van Ga » Wed, 26 Mar 2003 01:00:18

On Mon, 24 Mar 2003 14:33:41 -0000, "Ashley McConnell"


>Hi Folks,

>As it seems to be a slow news day in RAS-land I thought i'd spam my new demo
>:)

Hehe, I think the LFS 0.2 demo would have done that, but it's still
kinda quiet about it.

...

Nice! Do you already handle a bit of timing problems? (server time vs.
client time); prediction, extrapolation and that sort of stuff?

From a quick run, it felt as if the FF was a bit strong; so I quickly
got hard-left or hard-right forces. Although that is ofcourse a
car-specific thing, you still get more quickly into these wobbling
left-right vibration things when cruising on a straight piece of
road...

Heh, don't I know about those problems. ;-) Got something like that I
think in my latest version (v050 beta 11). Severe car drag at
low-speed (perhaps a direction error when feeding the relaxation
formulae).

One thing I noticed while glancing over a car.ini file is that the
relaxLengthLon > relaxLengthLat. Which seems odd, as mostly it's the
other way round (say L_lat=0.91, L=lon=0.091).
Might be a bug, but might be a butterfly after all. :)

Ruud van Gaal
Free car sim: http://www.racer.nl/
Pencil art  : http://www.marketgraph.nl/gallery/

Ashley McConnel

Sirocco Racing : New Sim Demo

by Ashley McConnel » Wed, 26 Mar 2003 01:24:15



> On Mon, 24 Mar 2003 14:33:41 -0000, "Ashley McConnell"

> >Hi Folks,

> >As it seems to be a slow news day in RAS-land I thought i'd spam my new
demo
> >:)

> Hehe, I think the LFS 0.2 demo would have done that, but it's still
> kinda quiet about it.

Hopefully i'll get a chance to give it a run tonight :))

I have done a little of all of that, some of it myself and some from the
library i am using (http://www.rakkarsoft.com).  It is by no means any good
yet, but I think i have the basis for a good amount of players.  I will of
course have be drastically reduce the number of bits i use to send
everything, just want to get it working for the moment before looking at
compression.  Any progress on Racer becoming multiplayer goodness?  That
would be fun :).  Good thing about starting multi is that replays and
ghost-cars should drop out fairly easily (simply a pretend network car!).
It'll be a start anyway :)

Those settings are fine for my MOMO, I get a fairly similar feeling to when
I am driving GPL.  Its not too strong really, although with your MSFF(?) the
maximum force may be different.  As a test you could simply change the
strength (0.3 currently IIRC) to perhaps 0.1 or 0.2.

Axes, you cant live with em.....you cant live without em ;)

From what I read from the paper (a while ago now!) was that the relaxation
length was the amount of the circumference that it took the tyre to produce
its "normal" (i.e. the force if we werent using the relaxation model).  I
thought that the longitudnal would take longer to get up to this speed, but
thinking about it now - this effect is probably due to the flex in the tyre
which would be greater laterally?  I'll fiddle with the file and see what
comes out :)

All the best,
Ash
http://www.siroccoracing.com

Ruud van Ga

Sirocco Racing : New Sim Demo

by Ruud van Ga » Wed, 26 Mar 2003 19:57:26

On Mon, 24 Mar 2003 16:24:15 -0000, "Ashley McConnell"




>> On Mon, 24 Mar 2003 14:33:41 -0000, "Ashley McConnell"

>> Hehe, I think the LFS 0.2 demo would have done that, but it's still
>> kinda quiet about it.

>Hopefully i'll get a chance to give it a run tonight :))

Hopefully I'll get a new computer before I try. ;)

...

Interesting, never heard of that. I have mostly based my (beginning)
code on Quake source and Phil's HawkNL semantics.

There is some working, but it doesn't interpolate yet (so an update
frequency of 20Hz still gives shocky cars), and there are is no time
infrastruture yet (I'd better think that through and understand it
before I start, though I have some idea through a book about DX7
programming, not sure about the title anymore).

Indeed. :) Although I do have replays, I am a bit hesitant on sharing
the code for network play. In network play, bandwidth limits and
compression start to matter, whereas for replays it's not that
important. But still, it may be worthwhile to get the two mixed a bit;
at least for event generation.
A ghost car I would do with 2 pointers in the replay: the start and
endframe. Still, there are enough syncing issues and drawing issues.
First have to get a new gfx engine in, to avoid (gfx)code that gets
thrown away later on.

...

They make a lot of difference; for the Mac I have a Logitech Wingman
Formula Force GP, and that gives hardly tough forces. I like the MSFF
in that respect.

Ok, thanks. I now & then think about a *** test; use a measuring
spring and attach that to the wheel. Then apply a force to the wheel,
and input the force that is measured into the computer, so the
computer can really generate the 'exact' forces.
Really simple, but a bit *** and for high-end only. But I
discovered a bug in my FF code (still there), where I just add Mz of
the front wheels together and use that for the FF force. I instead
should divide by the steering ratio.
I discovered that when I actually felt a high-end wheel that generated
the exact force you feed it, and it turned out 5Nm is pretty much! :)
(and my numbers are roughly around 40Nm).

They s... eh, rotate all the time! ;-)

...

Right.

Yup, compare longitudinal stiffness to lateral stiffness, or imagine
pushing a tire sideways and longitudinally. The SAE950311 document
also shows these values.

The bigger lateral relax len would make response a bit softer.

Ruud van Gaal
Free car sim: http://www.racesimcentral.net/
Pencil art  : http://www.racesimcentral.net/

Mikkel Gram-Hanse

Sirocco Racing : New Sim Demo

by Mikkel Gram-Hanse » Wed, 26 Mar 2003 19:36:00

I'll whip you online soon, just too damn busy right now.
Will download, will practise and will leave you in the dust when we meet in
Sirocco ***space :)

Mikkel


Ashley McConnel

Sirocco Racing : New Sim Demo

by Ashley McConnel » Thu, 27 Mar 2003 18:21:10


You probably will, I have been soundly thrashed in the past - 48secs!!!
Thats Impossible! :)

All the best,
Ash
http://www.racesimcentral.net/

Ruud van Ga

Sirocco Racing : New Sim Demo

by Ruud van Ga » Sat, 29 Mar 2003 19:09:14

On Mon, 24 Mar 2003 16:24:15 -0000, "Ashley McConnell"

...

Damn, now you've got me all e***d about network play again. ;-)
RakNet doesn't have a Unix edition yet, but I'm helping them out with
that. Seems like a nice library, but I've got a nice basis of my own,
but still, interesting.

I did some dead reckoning yesterday and this much improved the choppy
multiplayer updates in Racer. Have a method on paper now which should
give supersmooth warpfree holy-moly interpolation. :)
Ah, you never know until you see it running ofcourse. It's based on
the generic DIS concept (just to send pos,vel,acc and interpolate from
there as pos'=pos+t*vel+0.5*acc*t^2), and then adds splines to warp
smoothly upon packet updates (from a paper somewhere, I think it was
Gamasutra).
Interpolating the car's quaternions and restarting the spline halfway,
possibly throttling the spline advancement (in case the car is lagging
too much) should do the trick to deal with it all.
Can't wait to implement it... Not really difficult either fortunately.

It was already working by now, just looked awful. Now updates are
already looking reasonably playable, and wheel heights (no sinking
into the track), wheel rotation (just derived from car velocity right
now) and smoke/skidmarks are all done now (smoke derived from
slipratios that I send).

Ruud van Gaal
Free car sim: http://www.racesimcentral.net/
Pencil art  : http://www.racesimcentral.net/


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