rec.autos.simulators

  Just curious.  Somebody wrote an engine swapper utility for GPL awhile back.
Anyone know how this works?  What I'm wondering is, does anyone know how to
access the different engines' torque curves (I figure the other of the program
would know, are you here)?  If so, perhaps the community would be interested in
an engine simulator for Grand Prix Legends in the future that would let you
manipulate heads, camshafts, compression, exhaust and intake piping, etc...
Any thoughts?

 Thanks,

Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://www.racesimcentral.net/

I have those link on my linkpage :
http://www.bonghead.org/racing/gplstart/index.html

Stefan Zscharnack

<snip>

If you do this, *please* include some way that people can tell if
others are running modded cars - the original Engine Swapper caused
enough problems in this department until things settled down. Otherwise
we really could see large-scale cheating.

(Not that I wanted to bring this up again, but this was the real reason
I'd have liked to have seen an open-source VROC [yes, I know, and
accept, that this just isn't going to happen], to accommodate future
developments without waiting months for an official new version.)

--
Sceptical scrutiny is the means, in both science and religion, by which
deep insights can be winnowed from deep nonsense -- Carl Sagan

The GPL Scrapyard returns (slowly): http://www.hillclimbfan.f2s.com

Interesting, certainly. I got a Ferrari 312 torque curve from someone
recently; it was simulated with 'Engine Analyzer 3'. I don't know
whether the specs of the engine came with the product though.

If you get your hands on the torque curves, I'd certainly would also
like to know; still cloning a Ferrari from GPL (still need good
rollcenter values for such a car).

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

  Thanks, Stefan.  Perhaps I can drop the author an email now :0)

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

  I'm basically considering writing a similar program to Engine Analyzer 3.  My
QuickEngine Builder is a little too simplified for my tastes (an early
experiment from many years ago that worked surpisingly well), but could be
great with some additions and a new modelling approach.  

  I'll let you know if I get access to the stuff.  Will have to write the
author of the engine swapper utility for info.  If you can pull out the Ferrari
model with its suspension system and give me some specs on it, I should be able
to give you a decent roll center position...  Of course, the physics roll
center may not match up to the graphics though...  

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

It was very nice to see a F3 car with 140 bhp revving to 10k instead of the truck
like 5000 of GPL. I think I have the replay of it somewhere...

The trouble with GPL is that it performs no checksum checks when allowing clients
to connect to the server. So, an engine tuner would compromise the game and league
integrity, UNLESS the new version of VROC performs some kind of integrity checking.
Hmmm, maybe I should contact the people currently programming it... I have a few
ideas how it can be done.

---Asgeir---

--
  -asbjxrn

Cool, hope it works out.

The suspension seems to move quite a bit, but I always thought
rollcenters didn't vary THAT much (at least GPL uses static ones).
I'll see what I can do. I'm trying to port the GPLEA Eagle (improved
my 3DO loader quite a bit), but GPL uses BSP trees merged with LOD
models, and I think even adds collision planes/trees inside the 3DO,
so it's a bit of a mess considering today's rendering systems.
Converting that to a straight-on linear model is very inefficient and
my optimizer will have to thoroughly dig through the mess not to make
the car impossible to use (slow to render).

I did have some good results with a couple of 3do's; just missing a
lot of the images (must convert them all from MIP to BMP or TGA), and
the polygons don't seem to care about culling; I've got the wheels but
the front and back tire walls were oriented in the same world
direction; meaning always one of them is culled (unless I disable
culling, but well, that doesn't make things faster).
I created a flip-face for that, but it turned out that the rim of the
tire *** was connected in the same subtree and that was flipped in
the opposite direction again! So I must even flip per polygon, which
is a terrible nuisance. :( (and more coding)

I'll have to ask GPLEA for some info on the precise structure of the
Eagle; lots of .3do's and I'm not clear yet on how it all fits
together.

Perhaps someone has info on the suspension though?

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

SLG

  Geeze, Ruud!  I'm still trying to get your DOF files to load more than one
object, and JUST the vertices and indices for display!  lol  Someone did send
code for loading .3ds, .ace, and .obj files.  Just in case you haven't seen it
yet, check here:

http://www.gametutorials.com/Tutorials/Advanced/OpenGL_Pg3.htm

  Although by the sounds of what you just attempted to explain to me (whoosh,
over my head), you probably could write this stuff yourself in about 5 minutes
:0)

  Just had an idea.  If you want, send me a zoomed in shot from the front and
rear (close to parallel projection that way) that shows the front and rear
suspension.  I'll see what I can do :0)  Also, if you have the track width,
that would help scale things a bit.  I might be able to give an idea how much
the rc might be moving (or not moving.)  Of course, if someone pops in here
with some numbers, nevermind... :0)

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

 Good idea.  I suspect that the engine torque curves are fixed, rather than
generated from the chamber volume and all of that, but still, that's the place
to start.  What I was hoping is that these fixed curves could be rewritten by
the GPLEngine Designer (or whatever) using physical engine data like you just
described.  I know I can do the simulation with the physical stuff reasonably
well, but first I'd need to know how to access and change those parts of
GPL.exe as you pointed out.  

  I'll try your suggestion when I get some time, thanks.

  I have no idea how client/server stuff works, but if you wanted to contact
them, go for it.  It might be best to wait until (if) I can find and extract
the torque curves.  If the author of the engine swapper utility would help,
that would... well... help! :0)  

  I surely wouldn't want to mess up anybody's regular racing stuff though or
assist anybody in attaining "creative victories" ;-), so I'd be open to any
sort of security stuff that was necessary.  Perhaps a few bytes could be
written somewhere in gpl.exe by GPLEngine Designer if it had been used to
modify any engines, which would immediately show up in a checksum.  Can a
checksum even be run through a server this way?  If so, gpl.exe's that had been
modified by the engine swapper utility wouldn't pass either.  That'd be great
for the people that want to race "pure" GPL.    

  I'm just kicking the idea around right now though.

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

Ah, interesting. Never seen that one before.

Hehe, probably not. It took quite some time to get a GPL track
renderer, sort of. The 3DO format has been described in quite some
detail by Phil Flack. The problem is turning a rendering tree back
into some linear bunch of vertices. I just 'render' away into triangle
bursts and just see what happens though. :)

I'll spend some time somewhere in the next couple of weeks on trying
to figure out the Eagle models, so I can find the suspension (there
was a suspension shot on the GPLEA page, but not entirely from the
front I think).

The Eagle has a wheelbase of 245.1cm, and track width of 152.4cm both
at the front and the rear. Straight from the GPL info screen. :)

The guys from Engine Analyzer also did a Roll Center Calculator. Might
be something for your efforts too...
I'll see if I can find the suspension model in the jungle of 3do's.

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

  Sounds a little like what I've been trying to do with your DOF's....  I get
some funny looking cars sometimes :0)

  If/when you get the model working, send me a pic.  I've got 1/2 a roll center
calculator running (made it to develop the suspension model.)  It'll do just
fine for getting the rc for the cars though.  Actually, I could use my current
engine to make a roll center calculator right now :0)  Wonder if it'd be worth
anything?  It's too bad my "competition" <tounge in cheek> doesn't send me
sales figures :0)  Wish they did, it'd make project decisions quite a bit
easier!

  I'll be looking forward to the suspension pics.  If you can get a rear shot
too, that'd be good.

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