rec.autos.simulators

After reading some posts lasts week about open source sims being created by
a group I got very interested in giving it a try myself. So since several
days I've done quite some reading and trying and everything is coming to me
quite slowly. It's all in a very early stage but can you guys just give me
some advice on a few subjects. This will never go commercial since my
knowledge is just far too little, especially on 3d-programming. I just hope
you guys can help me out on this steep learning curve.

First of all could someone pass me the address of Nunnini's setup page, it
contains some physics which I intend on using. And other links on racing car
physics are welcome ofcourse (good books as well).
I've got no experience with track files at all, what do they contain
exactly? When using DirectX could a track be made of just one big .x file
(so a converted 3ds studio)?  Is there any usable track editor out there
which format I could easily use for my project?

So far I've set some goals of what I would like to achieve:
First of all I want this car driving on a drag strip.I'll try to model every
sensible component that I can (I've already dropped the engine, it's just a
matrix of revs, torque and power and some other variables now). I'll keep on
using that drag strip untill the physics are somewhat finished. By that time
I hope there will be a good way (and fairly easy one) to make tracks.

It will be open source, using Direct3D (I know it's not the best way, but
most books about directsound and directplay have a large portion covering
it, so costwise it's somewhat better.), modelling one Formula Ford car (no
AI), physics will go as far as my knowledge (and in the future maybe others)
will let it go, TCP-IP multiplayer.

As you see it's quite prestigious for someone with my experience, but it's
just to learn some new things and see what difficulties developers face when
making sims. I now have even ten times more respect for Papy creating GPL,
it's absolutely amazing how they have dealt with all those difficulties.

Please just post everything you know, I need the information badly.

I recently went down the same road, too. I think the choice of DirectX
is an obvious one, especially since it caters not only to the 3d cards
but also of the sound and networking. One could use OpenGL instead, but
since MS sadly didn't accept it as standard in Windows, it is not as
well supported.

A very good book on race car dynamics is Milliken & Milliken's 'Race Car
Vehicle Dynamics' (ISBN: 1560915269), but you would also need a book
that covers rigid body dynamics if you are not thoroughly familiar with
the topic. I can recomend H. Goldstein, Classical Mechanics (ISBN:
0-201-02918-9) that can be consider as one of the standard books in some
university physics courses, so it should be pretty easy to find it in
dedicated libraries.

I don't have any experience with programming DirectX, I am just starting
to learn (I only got as far as to initalize the 3D sreen so far :) ). If
you are still learning, too, perhaps we can discuss some more over
e-mail.

I hope I was able to help a bit,

-Gregor

Oh no! Now everybody is going for his own sim!  ;-)

Harjan, all the luck with your project, but this could be a
potentially negative evolution.. There aren't a *thousand* really
talented people out there with enough time to help developing a whole
ZOO of open source sims. So if they have to divide their attention
between 2-3 instead of 1 project, it probably doesn't help the
quality?

What about anticipating to this? Maybe contact Paul Hoad and
concentrate on a seperate physics engine, but with standard interfaces
so it could use the same format for objects,carshapes,textures, tracks
etc.? Or at least try to work out some tools for easy conversion?

Just an idea...

JoH

Remco

The problem with these things is that most people quit their project after
some months hard work. Leaving the rest of the group in despair. To avoid
this I plan on doing most of the things myself, with preferably the
help/information of others. That way I want to create some sort of a
platform from where others can join in and customize the project.
I also realize there's a big change of myself quitting after a couple of
moments, but at least it won't affect others. So please just support me and
tell me everything there is to know on this subject, because I need the
support.

Harjan.

Unfortunately, I don't have the tiniest clue about anything that is
needed to develop a sim <G>

I can be testdriver, and that will be all I'm afraid.

JoH

Sorry to hear about the Audi drive.

A colleague (slow driver) had a corporate day out driving various Audis &
others - at a Palmer run location (Bedford?). Anyway the finale was a
Formula Palmer Audi drive - boy was I envious :(

Tony

Book:
Milliken & Milliken's 'Race Car Vehicle Dynamics" ISBN:1-56091-526-9

Links:
Physics:
http://www.psky.com/
http://www.nas.nasa.gov/Services/Education/Resources/TeacherWork/Race...
http://www.d6.com/users/checker/
http://members.home.net/rck/phor/index.html
http://www.techreview.com/articles/oct99/cavanaugh.htm
http://www.sae.org/
http://www.jasc.com/
http://www.cs.berkeley.edu/~mirtich/massProps.html
http://www.magic-software.com/gr_misc.htm
http://www.cs.cmu.edu/~baraff/sigcourse/index.html
http://aerodyn.org/Annexes/Racing/racing.html

Fileformats:
http://www.wotsit.org/

You need to create your own trackformat. Forget the X-file format, you
better create your own. (Although you CAN use Xfiles in D3DIM, and the
Xfile format is documented. And there is a conversiontool X<->3DS. But
in the end, I think you'll go to use your own file format anyway...)

I think you'll come to the conclusion you've to create a trackeditor
yourself, al be it in the form of multiple tools or in a full blown
WYSIWYG version. With the latter you enable others to create tracks.

I think that DirectX is the best way to go if you want to reach the
most videocards. Since you're not planning to go commercial, you also
can use Glide or OpenGL. For my own project I decided to use DirectX7.
As you said, DirectPlay is good for multiplay. And as a bonus, an
example of DirectSound in the Dx7 SDK, when used with a GPL engine
sound, produces the same result as in GPL.

Also, an example of DirectInput in the Dx7 SDK is already usuable, and
include ForceFeedback.

Tools:
Go for VC6 and the DirectX7 SDK.

Tips:
Don't use the D3D Retain mode, go for the Immediate mode. Also take a
look to the D3DX functions. When you start, start with D3D. You need a
lot of what you learn there in the other parts of your project.
Concentrate on views, models, lights and materials.

After that, focus on timing. You need to update the physics x times a
second, and for a good result you need at least 250Hz. (GPL uses 288
Hz). You also need to find out when to update the display. Remember, a
smooth framerate is better then a fast framerate. (100 FPS is no good
when those 100 frames are displayed in the first halve of a second, if
in the next halve there are no frames at all)

Now you can do graphics, and you've thought about the timing. Time for
the physics. IMO better go for real physics (6DOF), don't start with
faking the car behaviour. Focus on Rigid Body Dynamics. See my links
for some information on physics. You will like the first one...

Only now you can start on designing/coding  your program. You can
probably reuse some code you wrote while learning the concepts.

The Sound, Controller, User Interface and Networkcode is next, but
that will be a breeze if you've the other stuff working. Oh, before I
forget, you need math...loads of it <g>

Hope this was any help....

Success!

Remco

PS

You can follow the status of my project on:

http://www.rmoedt.cistron.nl/

I'm still in the Direct3D stage, playing with views. So, no need to
visit that page if you're only interested in driving a car...warned
ya!