rec.autos.simulators

I attempted to update the Record for this track.  I plugged in Tracy's
qualifying time.  The resulting speed when I loaded the track was about
3 mph faster than the actual speed posted by EDS scoring.

Does this indicate that the time/scoring in the simulation is also
wrong?  Does this have something to do with the fact that the track in
real life is actually shorter than 1-mile?

Rick, can you shine your infinte wisdom and knowledge on this?

--
**************************** Michael E. Carver *************************
     Upside out, or inside down...False alarm the only game in town.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./.  [-  < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

Yes, it does. The 3D models of several of the tracks do not exactly match
the lengths in the <track>.TXT files, so your times/speeds do not
correspond to what you think they should.

I'm trying to get a list together of how long ICR2 thinks each track is so
that we can put it in the README.TXT for DOS 1.1 and Windows 95/Macintosh
1.0...

Rick Genter
Technical Lead, IndyCar Racing II
Sierra On-Line, Inc.

I suspect that the difference has to do with how the track length
is defined.  You can actually MEASURE the lap time, but you
can't measure the average lap speed.  The lap speed (whether in
the sim or in real life) is COMPUTED from the lap time and the
track length.  It's hard to say what the true track length is, as this
depends on how you decide to measure it.  For example, you could
measure the track length as the length of the inside white line; as
the length of the outside white line; as the length of the center of
the track; as the length of the racing line; ...

If the sim is reporting an average speed 3 mph faster than the
speed reported in real life, that is because they have defined the
track length to be slightly longer than CART (or whoever).

These track lengths are somewhat arbitrary anyway, so IMHO
Papyrus should have found out from CART (or whoever) what
they were using for track length and used the same value.

FYI, the track lengths used by Papyrus for the speed calculations
are also different between ICR1 and ICR2.  You might try putting
Tracy's time into ICR1 and see what speed is reported then.

--

Mike Corrigan

: >Does this indicate that the time/scoring in the simulation is also
: >wrong?  Does this have something to do with the fact that the track in
: >real life is actually shorter than 1-mile?
: >

: Yes, it does. The 3D models of several of the tracks do not exactly match
: the lengths in the <track>.TXT files, so your times/speeds do not
: correspond to what you think they should.

: I'm trying to get a list together of how long ICR2 thinks each track is so
: that we can put it in the README.TXT for DOS 1.1 and Windows 95/Macintosh
: 1.0...

: Rick Genter
: Technical Lead, IndyCar Racing II
: Sierra On-Line, Inc.

Well I have done some calculations and ICR2 thinks this track is  0.9872
miles long.  It may actually be this in real life too.  During ABC's
coverage of the race one of the announcers mentioned that the track is
actually less than a mile in length.  I just can't find any place that
says this is anything but a 1-mile oval, however.

So if you want to put Paul Tracy's new record in the RECORDS.TXT file
and want the speed to show his actual speed use the number 19115, this
should produce the speed of 190.737 in the record box.

Now what this means is that our records are inflated by 1.28% over
actual times on the real track.

I am wondering if Papyrus miscalculated the RELS number for this track
in the NAZARETH.TXT file. . .

--
**************************** Michael E. Carver *************************
     Upside out, or inside down...False alarm the only game in town.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./.  [-  < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

It's not the times that are off, but the speeds.  The times reported are
correct, it is the calculated speeds which don't match.  Of course, it is
difficult to say how 'long' a track is as it depends on the line you decide
to measure.

The RELS number has no affect on either the measured time nor the
calculated speed.

--

Mike Corrigan

: It's not the times that are off, but the speeds.  The times reported are
: correct, it is the calculated speeds which don't match.  Of course, it is
: difficult to say how 'long' a track is as it depends on the line you decide
: to measure.

But there is a correlation between speed/time/distance.  The time to
travel a measured amount of distance is where the speed comes in.  They
calulcate the speed by dividing the distance by time.  Since they have
the length of the track off, this will affect the speed as well as the
time.  At a give speed it will take longer to traverse 1 mile than .928
miles.  It's all tied together.

: The RELS number has no affect on either the measured time nor the
: calculated speed.

But, if the calculations are off RELS needs to be adjusted to either
slow down or speedup the field to bring it in line with the real speeds
run an a track of greater distance.
: Mike Corrigan

--
**************************** Michael E. Carver *************************
     Upside out, or inside down...False alarm the only game in town.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./.  [-  < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

In fact, ICR2 uses EXACTLY the same physical model for the tracks
as ICR1 does.  What is different in ICR2 is the number used for the track
length when computing the speed.  It is as if they decided to measure
the existing track's length on a different line, thus coming up with a
different value.  For example, let's suppose that Tony George decided
to remeasure the length of the track at Indy.  He picks a particular
line around the track and measures it as 2.55 miles.  That wouldn't
have any affect on the TIME a car takes to complete a lap, but it
would have an affect on the SPEED calculated from the time.
For example Tony Stewart had a practice lap yesterday with a
lap time of 38.116 seconds.  His reported speed was 236.121.  With
the length specified as 2.55 miles his reported speed would have been
240.844.  His time (and the actual track) wouldn't have been affected
at all.

If Papyrus changed the constant they use to compute speed from time
so that they would report the same lap speed for a given lap time as
would happen in real life, that wouldn't have any affect on how much
time it took for the AI to get around the track (nor on how fast you
can get around the track).

--

Mike Corrigan

: They do calculate the speed by dividing the distance by time.  The time
: is MEASURED (i.e. with a clock).  Having the wrong track length does
: not affect the time in any way.  Of course, you could argue that the
: simulation might allow you to get around the track in less time if it
: thought the track was shorter, but I don't think that is the problem.

: >But, if the calculations are off RELS needs to be adjusted to either
: >slow down or speedup the field to bring it in line with the real speeds
: >run an a track of greater distance.

: If Papyrus changed the constant they use to compute speed from time
: so that they would report the same lap speed for a given lap time as
: would happen in real life, that wouldn't have any affect on how much
: time it took for the AI to get around the track (nor on how fast you
: can get around the track).

I guess we are straying away from the original point.  I guess I am
concerned that Papyrus's programs may be using the wrong track length to
calculate speed and time.  Is the problem only in the RECORDS.TXT file
or all of the results skewed?  This question is based on Rick' following
reply which appeared earlier in this thread:

Newsgroups: rec.autos.simulators
Subject: Re: ICR2: Nazareth Timing Bug?
Date: 29 Apr 1996 19:31:10 -0400

Yes, it does. The 3D models of several of the tracks do not exactly match
the lengths in the <track>.TXT files, so your times/speeds do not
correspond to what you think they should.

I'm trying to get a list together of how long ICR2 thinks each track is so
that we can put it in the README.TXT for DOS 1.1 and Windows 95/Macintosh
1.0...

Rick Genter
Technical Lead, IndyCar Racing II
Sierra On-Line, Inc.

--
**************************** Michael E. Carver *************************
     Upside out, or inside down...False alarm the only game in town.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./.  [-  < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

My point was that they don't use the track length (right or wrong) to
get the lap time.  The lap time is measured using your CPU's timer.

The lap speeds are computed from the measured time using an
arbitrary track length.  It is clear that the track length used by
Papyrus in ICR2 is different than the length used in real life (by
CART, or whoever).  That is why the lap speed reported by ICR2
is different than you would see in real life (for a lap with the same
lap time).  It is also different than the value they used in ICR1 even
though the physical models of the tracks are identical between
ICR1 and ICR2.

As far as I can tell (and I've spent a lot of time working on this to
get EDITRPY to report the 'right' lap speeds) ICR2 uses the same
track length when converting the times recorded in the
RECORDS.TXT file as it does when computing your lap speeds
from your measured lap times.  The net: all of the results are
skewed.

I don't think that these changes are inherently 'right' or 'wrong' as the
track length is arbitrary anyway. (how do you measure the length of a
track with a finite width anyway?)

--

Mike Corrigan